Medición informal del p-valor mediante simulación

Existe un creciente reconocimiento de la importancia de desarrollar el razonamiento inferencial informal (RII) antes de aprender los conceptos formalmente. No obstante todavía hay poca investigación sobre su desarrollo en el aula en el nivel bachillerato (15-18 años). En situaciones informales, la principal dificultad es medir el p-valor de un estadístico, debido que no se tiene la noción de distribución muestral de forma natural. En el presente estudio se analiza el razonamiento de estudiantes de bachillerato para medir el p-valor de un estadístico al usar una aplicación dinámica que crea una distribución muestral empírica mediante la simulación computarizada. Se encuentra que la mayoría de los estudiantes miden el p-valor adecuadamente con ayuda de la simulación, lo que representa un cambio significativo en el RII

El aprendizaje desde la instrucción : la evolución de las estrategias personales en tareas de proporcionalidad numérica

This study examines the personal strategies evolution used by students in numerical proportionality task solving during instruction. The analysis of a sequence of video/audiotaped lessons allowed the observation of the process of cognitive construction by students in the classroom. The «local» effectiveness of intuitive strategies is considered a phase in the construction of more general strategies

Program development using abstract interpretation (and the ciao system preprocessor)

The technique of Abstract Interpretation has allowed the development of very sophisticated global program analyses which are at the same time provably correct and practical. We present in a tutorial fashion a novel program development framework which uses abstract interpretation as a fundamental tool. The framework uses modular, incremental abstract interpretation to obtain information about the program. This information is used to validate programs, to detect bugs with respect to partial specifications written using assertions (in the program itself and/or in system librarles), to genérate and simplify run-time tests, and to perform high-level program transformations such as múltiple abstract specialization, parallelization, and resource usage control, all in a provably correct way. In the case of validation and debugging, the assertions can refer to a variety of program points such as procedure entry, procedure exit, points within procedures, or global computations. The system can reason with much richer information than, for example, traditional types. This includes data structure shape (including pointer sharing), bounds on data structure sizes, and other operational variable instantiation properties, as well as procedure-level properties such as determinacy, termination, non-failure, and bounds on resource consumption (time or space cost). CiaoPP, the preprocessor of the Ciao multi-paradigm programming system, which implements the described functionality, will be used to illustrate the fundamental ideas

Wetland restoration and nitrate reduction: the example of the periurban wetland of Vitoria-Gasteiz (Basque Country, North Spain)

Changes in land use and agricultural intensification caused wetlands on the quaternary aquifer of Vitoria-Gasteiz (Basque Country) to disappear some years ago and nitrate concentration in groundwaters increased very quickly. The Basque Government recently declared the East Sector of this aquifer a Vulnerable Zone according to the 91/676/CEE European Directive. Recently, the wetlands have been restored through the closure of the main drainage ditches, the consequent elevation of the water table and the abondonment of agricultural practices near the wetlands. This is the case of the Zurbano wetland. Restoration has allowed the recovery of its biogeochemical function, which has reduced nitrate concentrations in waters. Nitrate concentrations which exceed 50 mg l–1 in groundwaters entering into the wetland are less than 10 mg l–1 at the outlet. Conditions in the wetland are conducive to the loss of nitrates: organic matter rich wetted soils, clay presence allowing a local semiconfined flow and very low hydraulic gradient. Water quality monitoring at several points around the wetland showed the processes involved in nitrate loss, although some aspects still remain unresolved. However, during storm events, the wetland effectively reduces the nitrate concentration entering the Alegria River, the most important river on the quaternary aquifer

Evidences of evanescent Bloch waves in Phononic Crystals

We show both experimentally and theoretically the evanescent behaviour of modes in the Band Gap (BG) of finite Phononic Crystal (PC). Based on experimental and numerical data we obtain the imaginary part of the wave vector in good agreement with the complex band structures obtained by the Extended Plane Wave Expansion (EPWE). The calculated and measured acoustic field of a localized mode out of the point defect inside the PC presents also evanescent behaviour. The correct understanding of evanescent modes is fundamental for designing narrow filters and wave guides based on Phononic Crystals with defects.Comment: 8 pages, 3 figure

El conocimiento acerca de las matemáticas y las prácticas de enseñanza

The individual and contextual influences that two periods of school experience have over the way in which two prospective teachers build their personal view of Mathematics and its teaching are studied. In particular, the important role played by the perceived knowledge of the subject matter knowledge is shown. Also, the strategies used in trying to give coherence and meaning to the experimented changes are discussed

The CIAO multiparadigm compiler and system: A progress report

Abstract is not available

Introducción de las técnicas de modelización para el estudio de la física y de las matemáticas en los primeros cursos de las carreras técnicas

In this article we present a program of interdisciplinary practices for a first engineering course. We followed this program during the course 1996-1997, and we give several examples of the kind of exercises that we used. We also present some remarks and conclusions that we have achieved in our experience. Our purpose is to introduce a teaching strategy for Mathematics and Physics at the University level

Density and reproductive characteristics of female brown bears in the Cantabrian Mountains, NW Spain

Here we present annual nearest-neighbour distances (as a proxy of density) between females with cubs-of-the-year (hereafter FCOY) and reproductive characteristics of brown bears Ursus arctos in the Cantabrian Mountains (NW Spain), from 1989 to 2017. FCOY nearest-neighbour distances and reproduction parameters of 19 focal females followed over several consecutive years (from 2004 to 2017) were obtained from bears inhabiting the western sector of the Cantabrian Mountains, where most of the bear population resides. In contrast, general reproductive characteristics were studied in the whole Cantabrian Mountains (western and eastern sectors together) on a sample of 362 litter sizes and 695 cubs. Mean nearest-neighbour distance between FCOY was 2559 ± 1222 m (range = 1305–4757 m). Mean litter size was significantly larger in the west (1.8 ± 0.2 cubs) than in the east (1.3 ± 0.6 cubs). Mean litter size for the whole of the Cantabrian Mountains was 1.6 ± 0.3 cubs. Litter sizes of one, two and three cubs represented 33.4, 56.1 and 10.5% of observed family groups, respectively. Interannual variations in litter size were not significant for both the western and the eastern areas. Mean cub mortality was 0.2 ± 0.5 cubs and did not vary among years. Cub mortality per litter size was 3.9% for one cub, 69.2% for two cubs and 26.9% for three cubs. Mean reproductive rate of the 19 focal females was 1.5 ± 0.6 cubs (n = 58 litters). Litter size of focal FCOY did not differ from the litter size obtained from systematic observations in the whole Cantabrian Mountains. During this period, cub mortality occurred in 24.1% of the 58 litters. Females usually bred every second year (average litter interval = 2.2 years). The estimated reproductive rate for the bear population was 0.7 young born/year/reproductive adult female