Logfile-Analysen: Möglichkeiten und Grenzen ihrer Nutzung bei Untersuchungen zur Mensch-Maschine-Interaktion

Die Aufzeichnung der Computernutzung in automatisch generierten elektronischen Protokollen – so genannten Logfiles – entwickelt sich zu einer zunehmend genutzten Erfassungsmethode bei Untersuchungen der Interaktion zwischen Mensch und Computer. Dieser Beitrag bietet einen einführenden Überblick über Verfahren der Logfile-Aufzeichnung und der Analyse der Daten. Neben einer Erläuterung der Begrifflichkeiten werden sowohl Vor- und Nachteile von Logfile-Auswertungen als auch grundlegende Methoden, mathematische Beschreibungen des Nutzerverhaltens und Ansätze der Typisierung von Nutzeraktivitäten dargestellt

Estrategia para la enseñanza de límite de una función

La definición delta-épsilon de límite de una función en general no es comprendida cabalmente por los estudiantes, quienes frecuentemente separan lo conceptual de lo algorítmico, y por ello, en un intento de mejorar su proceso de enseñanza-aprendizaje, es que hemos diseñado una estrategia didáctica para la enseñanza de este tema para los alumnos del primer año de la Facultad de Ingeniería. Presentamos el diseño de la estrategia, las actividades propuestas y el resultado de la experiencia aúlica

Ziviz-Survey 2012 : Zivilgesellschaft Verstehen

Organised civil society in Germany is a neglected area of statistical observation. The project ZiviZ (civil society in figures) of the Donors' Association for German Science together with the Bertelsmann Foundation and the Fritz Thyssen Foundation wants to bridge this gap and has first taken the third sector under the microscope. The data collected from representative civil society structures and processes provide guidance on key issues in the field of organized civil society for the first time

Propuesta metodológica para la enseñanza del Cálculo.

Es frecuente que los estudiantes de Cálculo separen lo conceptual de lo algorítmico, por ello, en un intento de mejorar el proceso de enseñanzaaprendizaje del Cálculo en alumnos del primer año de la Facultad de Ingeniería de la Universidad Nacional de Jujuy, hemos centrado nuestro interés en la búsqueda de estrategias adecuadas para enseñar y aprender matemática . En la enseñanza tradicional los temas desarrollados dependen de las definiciones conceptuales, lo que a menudo resulta poco significativo y se pierde valor en su aprendizaje cuando se debe realizar las conexiones entre las representaciones gráficas, numéricas y algebraicas. Así, hemos diseñado y ensayado secuencias didácticas para superar la dificultad observada en nuestros alumnos para conceptualizar. Empleamos Ingeniería Didáctica como metodología y objeto de la investigación; en particular ensayamos en 2007 y 2008 secuencias para: conceptualización de la definición de límite; aprehensión del concepto de derivada en la modelización mediante ecuaciones diferenciales y comprensión significativa del proceso límite de una suma asociado a la integral definida. Es importante trabajar en la búsqueda de la metodología más adecuada al entorno de los alumnos que contribuya a la construcción de los esquemas de conocimientos sólidos necesarios para emplear el Cálculo en los estudios posteriores

ZBTB16 is a sensitive and specific marker in detection of metastatic and extragonadal yolk sac tumour

Aims Accurate histological diagnosis and classification of germ cell tumours (GCTs) is key to informing successful therapeutic and surveillance strategy. The modern therapeutic approach for yolk sac tumour (YST) is highly curative. Because YST takes on a large morphological spectrum, it can be confused for other GCT subtypes as well as somatic carcinomas, particularly when YST presents in an extragonadal or a metastatic setting. Currently available immunohistochemical markers are limited by suboptimal sensitivity and specificity. We reported recently that ZBTB16 is a sensitive and specific marker for testicular YST. ZBTB16 is absent in other GCTs and in most common somatic carcinomas, including those of gastrointestinal, pancreatobillary, respiratory, genitourinary and gynaecological tracts. The purpose of this study is to investigate the diagnostic utility of ZBTB16 in the settings of metastatic and extragonadal YST. Methods and results We studied 32 archived metastatic and four extragonadal primary YSTs as well as 51 somatic malignancies for their immunohistochemical expression of ZBTB16. For comparison, α-fetoprotein (AFP) and glypican-3 were also studied in parallel. Our results demonstrated an overall sensitivity of 91.6% for ZBTB16 in detecting metastatic and extragonadal YSTs. The non-YST elements (teratoma and embryonal carcinoma) in 15 YST-containing metastatic mixed GCTs were non-reactive. With the exception of occasional myoepithelial cells of salivary gland carcinoma, all the 51 somatic malignancies were negative for ZBTB16. Conclusions ZBTB16 is a sensitive and specific marker for YST and is diagnostically superior to AFP and glypican-3 in metastatic and extragonadal settings

How to Investigate Within-Subject Associations between Physical Activity and Momentary Affective States in Everyday Life: A Position Statement Based on a Literature Overview

Several meta-analyses have investigated the association between physical activity and affective states and have found evidence suggesting that exercise exerts a positive effect on affective state. However, in this field of research, most studies have conducted between-subject analyses. Nonetheless, there is more and more interest in the within-subject associations between physical activity and momentary affective states in everyday life. This position statement pertains to this up-and-coming field of research and provides methodological recommendations for further studies. The paper is divided into three parts:First, we summarise and evaluate three methodological requirements necessary for the proper evaluation of within-subject associations between physical activity and momentary affective states in everyday life. We propose that the following issues should be considered: a) to address the dynamic nature of such relationships, repeated assessments are necessary; b) as activities performed in everyday life are mostly spontaneous and unconscious, an objective assessment of physical activity is useful; c) given that recall of affective states is often affected by systematic distortions, real-time assessment is preferable. In sum, we suggest the use of ambulatory assessment techniques, and more specifically the combination of acceloremeter-assessment of physical activity with an electronic diary assessment of the momentary affective state and additional context information. Second, we summarise 22 empirical studies published between 1980 and 2012 using ambulatory assessment to investigate within-subject associations between momentary affective states and physical activity in everyday life. Generally, the literature overview detects a positive association, which appears stronger among those studies that were of high methodological quality.Third, we propose the use of ambulatory assessment intervention strategies to change people's behaviour (ambulatory assessment in

Assessing the quality of scientific explanations with networks

This article introduces a network approach to describe the quality of written scientific explanations. Existing approaches evaluate explanations mainly on the level of sentences or as a whole but not on the elementary level of single terms. Moreover, evaluation of explanations is often based on highly inferential scoring techniques. We addressed both issues by converting the elementary structure of terms in explanations into networks (so-called element maps) and analysing these with mathematical measures, thus extracting the size and complexity of an explanation, adequacy, coherence, and use of key terms. A total of 65 explanations of experts and students were analysed quantitatively and qualitatively. Differences between expert and student maps’ measures can be interpreted meaningfully against the background of existing research findings. Thus, we argue that our approach using network analysis provides a precise, fine-grained, and low-inferential tool that complements and refines existing approaches. Element maps have the potential to improve teaching and research by precisely revealing the strengths and weaknesses of explanations.Peer Reviewe

Assessment tool to understand how students justify their decisions in data comparison problems

The article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Students at all levels of education experience difficulties with the concepts of measurement uncertainties. One task that includes concepts of measurement uncertainties is a data comparison problem where students decide whether two datasets are in agreement or not—an authentic scientific practice. To aid students with these concepts and tasks, sensitive instruments are needed that probe students’ understanding and track their progress. We present a tool in the form of a coding manual that analyzes students’ written justifications for such a data comparison problem. With this coding manual, justifications are coded based on the quantity that is compared and the deciding criterion in this comparison. Our coding manual was used in the evaluation of a digital learning environment (DLE). In this evaluation, 154 participants (aged 14–17 years) wrote a justification for a data comparison problem before and after going through the DLE. These participants were randomly assigned to one of three groups where each group was taught an increased amount of concepts regarding measurement uncertainties. By analyzing the participants’ justifications with our coding manual, we could probe their ability to compare datasets on a fine-grained level. The sensitivity of our tool was illustrated by the increase in higher quality codes with the increased conceptual teaching between the three groups. We argue that our tool for coding justifications can be applied to any data comparison problem giving detailed information about what data analysis methods students use and how they reach their conclusion and thus contributes to the research on students’ understanding of measurement uncertainties.Peer Reviewe

Using measurement uncertainties to detect incomplete assumptions about theory in an experiment with rolling marbles

In this lab activity, carbon copy paper is used to record the horizontal distance a marble flies off a table after rolling down an incline. The minimal scatter of the dots visually shows the high precision—i.e. the small uncertainty—of the measurements to students. The theoretical prediction of this distance will be too big if students forget to include rotational energy in the energy balance when they calculate the marble’s speed at the bottom of the incline. This results in a discrepancy between the predicted horizontal distance and the measurement result. The precision of the experiment and the absence of overlap with the theoretical prediction is evidence that the prediction has to be wrong. Including rotational energy and taking a 10% energy loss due to friction into account, makes the measurement result overlap with the theoretical prediction, bringing them into agreement. Thus, measurement uncertainties guide the process of comparing the measurement result with the prediction: overlap between the theory-based prediction and the measurement result indicates agreement, whereas no overlap implies discrepancy. The lab activity presented here is an activity where measurement uncertainties are used in a meaningful, indispensable manner. The experimental result is evidence that forces students to rethink their assumptions, in this case about the conservation of energy. This leads to the revision of their calculation, emphasizing the necessity to include rotational energy and friction. Without it, the highly precise measurement result is in disagreement with the theoretical prediction. A procedure such as this—comparing empirical data with theory—is an authentic and common practice in science and should thus find its way into the physics classroom; but it cannot be done without an analysis of measurement uncertainties.Peer Reviewe

The spinning toilet brush–a classroom experiment on the mechanical equivalent of Joule's heat

Although Joule’s experiment on the mechanical equivalent of heat is well known and discussed in many introductory physics courses and textbooks, we are not aware of any version of this experiment that can be set up by lecturers or teachers using standard laboratory equipment. To fill this gap, we present a setup quite similar to Joule’s original experiment and show what kind of quantitative results can be obtained with it. It will be shown that temperature control is a major challenge, making Joule’s work even more impressive.Peer Reviewe