Acquiring the notion of learning hypotheses in mathematics teacher education

The notion of hypothetical learning trajectory has generated much interest among experts in mathematics education. It is proposed that this notion is a useful tool in teachers’ teaching practice and that it is necessary to prepare teachers in their capacity to formulate hypothetical learning trajectories about specific mathematics school topics. It is therefore also necessary to explore the learning processes that teachers undergo when learning this notion in their education. In this article, we introduce the notion of learning hypotheses as an adaptation of the idea of hypothetical learning trajectory (SIMON, 1995). We describe how the groups of secondary-school mathematics teachers that participated in a teacher education program understood and used this notion in order to determine the contribution of a set of tasks to a learning goal previously established. We found that the groups developed their knowledge of the notion of learning hypotheses and used it in a heterogeneous way, and that the education program was partly successful in its goal to make the groups of teachers learn and perceive the notion’s utility

Framework for automatic generation of ontology mappings

Some of the most outstanding problems in Computer Science (e.g. access to heterogeneous information sources, use of different e-commerce standards, ontology translation, etc.) are often approached through the identification of ontology mappings. A manual mapping generation slows down, or even makes unfeasible, the solution of particular cases of the aforementioned problems via ontology mappings. Some algorithms and formal models for partial tasks of automatic generation of mappings have been proposed. However, an integrated framework to solve this problem is still missing. In this paper, we present a framework for automatic ontology mapping generation, and a partial implementation of it. Our proposal is that this integrated vision can guide, not only our future work, but also the future work of other researchers. In the implementation carried out, we have built a mapping ontology with knowledge on ontology mappings

Dielectric study of the glass transition: correlation with calorimetric data

The glass transition in amorphous poly(ethylene terephthalate) is studied by thermally stimulated depolarization currents (TSDC) and differential scanning calorimetry (DSC). The ability of TSDC to decompose a distributed relaxation, as the glass transition, into its elementary components is demonstrated. Two polarization techniques, windows polarization (WP) and non-isothermal windows polarization (NIW), are employed to assess the influence of thermal history in the results. The Tool-Narayanaswami-Moynihan (TNM) model has been used to fit the TSDC spectra. The most important contributions to the relaxation comes from modes with non-linearity (x) around 0.7. Activation energies yield by this model are located around 1eV for polarization temperature (Tp) below 50C and they raise up to values higher than 8eV as Tp increases (up to 80C). There are few differences between results obtained with WP and NIW but, nonetheless, these are discussed. The obtained kinetic parameters are tested against DSC results in several conditions. Calculated DSC curves at several cooling and heating rates can reproduce qualitatively experimental DSC results. These results also demonstrate that modelization of the non-equilibrium kinetics involved in TSDC spectroscopy is a useful experimental tool for glass transition studies in polar polymers.Comment: 13 pages, 2 tables, 10 figures; minor change

Double glass transition in polyethylene naphthalate structural relaxation by MDSC, BDS and TSDC

We present the experimental study of the primary, $\alpha$, and secondary, $\beta^*$, relaxations of the glassy polymer polyethylene naphthalate (PEN), by Modulated Differential Scanning Calorimetry (MDSC), Thermally Stimulated Discharge Currents (TSDC) and Broadband Dielectric Spectroscopy (BDS). Results show how the $\alpha$ and $\beta^*$ relaxations can be considered part of a very broad and distributed relaxation. The $\beta^*$ relaxation is composed of a main contribution ($\beta_3^*$) and two additional ones ($\beta_1^*$ and $\beta_2^*$) and each elementary mode of the relaxation has its own glass transition temperature. This scenario gives rise to an extended glass transition mainly centered in $T_{g\beta^*} \sim 305$ K and $T_{g\alpha} \sim 387$ K

Efectos de la asistencia, densidad de la misma y la capacidad del pabellón en las victorias conseguidas en casa en función de la conferencia en la NBA

Los equipos que juegan en casa ganan más del 50% de los partidos. El estudio de los efectos relacionados con el apoyo del público ha sido poco analizado. El objetivo de este trabajo fue identificar los efectos de la capacidad del pabellón, la asistencia a los partidos y la densidad de la misma en las victorias conseguidas en casa. Se analizaron los resultados por equipo de 7 temporadas de la NBA (N=210). Los datos fueron extraídos de la página web especializada Basketball-Reference.com. La asistencia media, la capacidad del pabellón y la densidad de la asistencia y su relación con el número de victorias en casa fueron analizadas. Se utilizó un análisis de regresión para analizar los efectos de estas variables en el número de victorias en casa. Los resultados muestran un efecto estadísticamente significativo de la asistencia media al pabellón en ambas conferencias, y de la capacidad del pabellón en la conferencia oeste. El tamaño del público ya se ha demostrado como uno de los predictores más potentes de las victorias en casa. El aumento de la asistencia al pabellón va a llevar a un aumento del rendimiento de equipo. Los clubes deben promover políticas que hagan más atractivo desplazarse al pabellón por parte de los aficionados, aumentando la asistencia y, por tanto, el número de victorias en casa

Stau detection at neutrino telescopes in scenarios with supersymmetric dark matter

We have studied the detection of long-lived staus at the IceCube neutrino telescope, after their production inside the Earth through the inelastic scattering of high energy neutrinos. The theoretical predictions for the stau flux are calculated in two scenarios in which the presence of long-lived staus is naturally associated to viable supersymmetric dark matter. Namely, we consider the cases with superWIMP (gravitino or axino) and neutralino dark matter (along the coannihilation region). In both scenarios the maximum value of the stau flux turns out to be about 1 event/yr in regions with a light stau. This is consistent with light gravitinos, with masses constrained by an upper limit which ranges from 0.2 to 15 GeV, depending on the stau mass. Likewise, it is compatible with axinos with a mass of about 1 GeV and a very low reheating temperature of order 100 GeV. In the case of the neutralino dark matter this favours regions with a low value of tan(beta), for which the neutralino-stau coannihilation region occurs for smaller values of the stau mass. Finally, we study the case of a general supergravity theory and show how for specific choices of non-universal soft parameters the predicted stau flux can increase moderately.Comment: 26 pages, 7 figures. References added and minor changes. Final version to appear in JCA

Efecto de un programa de capacitación en competencias de investigación en estudiantes de ciencias de la salud

The European Higher Education Area implies a change to the Health Science education in Spain. Spanish university system must promote the acquisition of competences in research habits, such as the information management or scientific dissemination. This article presents the findings of a study to evaluate the level of effectiveness and satisfaction of an educational training program on research skills geared towards Health Science students. A hundred and eight students of Physical Therapy degree, Occupational Therapy degree and Nursing degree were participated into a quasi-experimental study. Educational needs were first detected by a questionnaire based on different research skills. A semi-distance educational training program was designed and implemented after defining the above-mentioned needs. This program significantly improved the perception of knowledge and skills in research competences. As well as the level of theory and practical content assimilated by the students significantly increased after the program. These findings suggest that incorporation of specific training that allow for students to come in contact with research, are effective at improving research competences for Health Sciences students.El Espacio Europeo de Educación Superior implica un cambio en la formación universitaria de Ciencias de la Salud en España. El sistema universitario debe promover desde el grado la adquisición de competencias básicas en investigación, como la gestión de información y la comunicación científica. Este artículo presenta los hallazgos de un estudio cuyo objetivo fue evaluar el nivel de eficacia y satisfacción de un programa de capacitación educativa en competencias de investigación dirigido a estudiantes de Ciencias de  la Salud. Se diseñó un estudio cuasiexperimental en el que participaron ciento ocho estudiantes de grado de Fisioterapia, Terapia ocupacional y Enfermería. En una primera fase se detectaron las necesidades educativas en competencias de investigación a través de un cuestionario; a continuación se implementó un programa de capacitación semipresencial y se evaluó el efecto alcanzado en las necesidades antes detectadas.  Este programa mejoró significativamente la percepción de los participantes en relación a su conocimiento y habilidad en competencias de investigación. Del mismo modo, las destrezas cognitivas y prácticas mejoraron considerablemente tras el programa. Estos hallazgos evidencian que la puesta en marcha de programas específicos de capacitación en investigación es efectiva para mejorar la adquisición de competencias a este respecto en estudiantes de Ciencias de la Salud

Dielectric study of the glass transition of PET/PEN blends

An analysis of the glass transition of four materials with similar chemical structures is performed: PET, PEN and two PET/PEN blends (90/10 and 70/30 w/w). During the melt processing of the blends transesterification reactions yield block and random PET/PEN copolymers that act as compatibilizers. The blends obtained in this way have been characterized by 1H-NMR and DSC. A degree of randomness of 0.38 and 0.26 has been found for the 90/10 and 70/30 copolymers. It is shown by DSC that this copolimerization is enough to compatibilize the blends. The alpha relaxation, the dielectric manifestation of the glass transition, has been studied by thermally stimulated depolarization currents (TSDC). The relaxation has been analyzed into its elementary modes by means of a relaxation map analysis. The activation energies of the modes of the glass transition do not change significantly between the four materials: in all cases the modes with a larger contribution have around 3 eV and modes with less than 1 eV are not detected. The change in the pre-exponential factor accounts entirely for the relaxation time change from material to material, that is larger as the PEN content increases. The compensation law is fulfilled and compensation plots converge for high-frequency modes. The polarizability decreases as the PEN content increases due to the increased stiffness of the polymer backbone. An analysis of the cooperativity shows that the central modes of the distribution are the most cooperative while high-frequency modes tend to behave more as Arrhenius. The low-frequency modes are difficult to study due to the asymmetry of the distribution of relaxation times. PEN turns out to be the less cooperative material. It is demonstrated how the parameters obtained from the dielectric study are able to reproduce calorimetric data from DSC scans and are, therefore, a valid description of the glass transition.Comment: 22 pages, 13 figure