TY - JOUR A1 - Herzog, Moritz A1 - Ehlert, Antje A1 - Fritz, Annemarie T1 - A Competency Model of Place Value Understanding in South African Primary School Pupils JF - African Journal of Research in Mathematics, Science and Technology Education N2 - Although the general development of mathematical abilities in primary school has been the focus of many researchers, the development of place value understanding has rarely been investigated to date. This is possibly due to the lack of conceptual approaches and empirical studies related to this topic. To fill this gap, a theory-driven and empirically validated model was developed that describes five sequential conceptual levels of place value understanding. The level sequence model gives us the ability to estimate general abilities and difficulties in primary school pupils in the development of a conceptual place value understanding. The level sequence model was tried and tested in Germany, and given that number words are very differently constructed in German and in the languages used in South African classrooms, this study aims to investigate whether this level sequence model can be transferred to South Africa. The findings based on the responses of 198 Grade 2-4 learners show that the English translation of the test items results in the same item level allocation as the original German test items, especially for the three basic levels. Educational implications are provided, in particular concrete suggestions on how place value might be taught according to the model and how to collect specific empirical data related to place value understanding. KW - Place value KW - Rasch test modelling KW - mathematical concepts Y1 - 2017 U6 - https://doi.org/10.1080/18117295.2017.1279453 SN - 1811-7295 SN - 2469-7656 VL - 21 SP - 37 EP - 48 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Herzog, Moritz A1 - Ehlert, Antje A1 - Fritz, Annemarie T1 - Kombinatorikaufgaben in der dritten Grundschulklasse BT - Darstellung, Abstraktionsgrad und Strategieeinsatz als Einflussfaktoren auf die Lösungsgüte JF - Journal für Mathematik-Didaktik N2 - Seit einigen Jahren werden kombinatorische Aufgaben als eigenständiges Thema im Mathematikunterricht der Grundschule behandelt, das diverse Lerngelegenheiten bereithält. Dies wirft Fragen zur Bearbeitungsweise sowie zu den Repräsentationen der Schülerinnen und Schüler auf. In einer empirischen Studie (N = 548) wurden anhand von sechs Kombinatorikaufgaben Leistungen und Bearbeitungsweisen von Lernenden in der dritten Klasse erhoben. Besonderes Augenmerk wurde auf die verwendeten Darstellungen und den Abstraktionsgrad sowie den Einsatz von Makrostrategien gerichtet. Diese drei Faktoren wurden hinsichtlich ihres Einflusses auf die Lösungsgüte untersucht. Die Ergebnisse zeigen, dass nicht alle Schülerinnen und Schüler ohne Anleitung geeignete Lösungsansätze zu kombinatorischen Problemen fanden. Die Darstellungsweise hatte einen vergleichsweise geringen Einfluss auf die Lösungsquote. Im Gegensatz dazu konnten unterschiedlich starke positive Zusammenhänge zwischen Abstraktionsgrad bzw. Strategieeinsatz und Lösungserfolg nachgewiesen werden. Aus den Ergebnissen der Studie lassen sich Schlüsse über die Vermittlung und didaktische Aufbereitung des Themenfeldes Kombinatorik in der Grundschulmathematik ziehen. N2 - For several years now, combinatorics has been taught as an independent mathematics topic in primary school that provides various learning opportunities. This raises questions about how learners actually solve and represent combinatorial problems. On the basis of six different combinatorics tasks, the performance and approach of pupils were assessed in an empirical study (N = 548). Particular attention was paid to the representation of the approach the children used, the degree of abstraction as well as the application of overarching (macro) strategies. The influence of each of these three factors on the quality of the solution was investigated. The results show that not all students were able to find suitable solutions for combinatorial problems without guidance. The representations the learners used had relatively little influence on the task performance. In contrast, influences on performance of levels of abstraction and use of strategies were found to varying degree. From the results of the study, conclusions can be drawn about the teaching methods used with regards to the treatment of combinatorics in primary school mathematics. T2 - Combinatorial Problems in Grade 3 Influences of Representation, Level of Abstraction and use of Strategies on Solving Success KW - Primary school KW - Combinatorics KW - Representation KW - Strategies KW - Grundschule KW - Kombinatorik KW - Darstellen KW - Makrostrategien Y1 - 2017 U6 - https://doi.org/10.1007/s13138-017-0118-8 SN - 0173-5322 SN - 1869-2699 VL - 38 SP - 263 EP - 289 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Fritz, Annemarie A1 - Long, Caroline A1 - Herzog, Moritz A1 - Balzer, Lars A1 - Ehlert, Antje A1 - Henning, Elizabeth T1 - Mismatch of the South African foundation phase curriculum demands and learners’ current knowledge JF - African journal of research in mathematics, science and technology education N2 - Against the background of the low mathematical performance of South African learners in international panel studies, there is an urgent need to improve mathematical education. In particular, the curriculum and its structure raise questions. It is logical that the prescribed curricula should align with learners' developmental trajectories. Given the hierarchical structure of mathematics, the curricular requirements should pay attention to learners' current knowledge of mathematical concepts. The aim of this study was to compare the curricular requirements as defined by the CAPS with the conceptual current knowledge of South African learners. South African Grade 1 learners (N = 602) were assessed on a test of numeracy concepts, based on a theoretically informed and empirically validated model of developing mathematical proficiency. The content of the CAPS for Grade 1 was aligned to the model levels by two experts (Cohen's kappa = .753, p < 0.001). Results show that the curricular requirements go far beyond the current knowledge required to engage with these new concepts of the vast majority of South African Grade 1 learners. The mismatch may to some extent be responsible for the unsatisfactory results in international comparison studies. These results show that the intended curriculum is beyond the grasp of most South African Grade 1 learners. These children are unlikely to develop new arithmetic concepts based on their lack of required foundation knowledge. We therefore argue that the intended curriculum for Grade 1 should focus more on counting skills, ordinal relations between numbers and-most importantly-set-based number representations and part-part-whole relations. KW - Arithmetic development KW - number concepts KW - curriculum development KW - mathematical learning difficulties Y1 - 2020 U6 - https://doi.org/10.1080/18117295.2020.1724466 SN - 1811-7295 SN - 2469-7656 VL - 24 IS - 1 SP - 10 EP - 20 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - GEN A1 - de Vera, Jean-Pierre Paul A1 - Alawi, Mashal A1 - Backhaus, Theresa A1 - Baque, Mickael A1 - Billi, Daniela A1 - Boettger, Ute A1 - Berger, Thomas A1 - Bohmeier, Maria A1 - Cockell, Charles A1 - Demets, Rene A1 - de la Torre Noetzel, Rosa A1 - Edwards, Howell A1 - Elsaesser, Andreas A1 - Fagliarone, Claudia A1 - Fiedler, Annelie A1 - Foing, Bernard A1 - Foucher, Frederic A1 - Fritz, Jörg A1 - Hanke, Franziska A1 - Herzog, Thomas A1 - Horneck, Gerda A1 - Hübers, Heinz-Wilhelm A1 - Huwe, Björn A1 - Joshi, Jasmin Radha A1 - Kozyrovska, Natalia A1 - Kruchten, Martha A1 - Lasch, Peter A1 - Lee, Natuschka A1 - Leuko, Stefan A1 - Leya, Thomas A1 - Lorek, Andreas A1 - Martinez-Frias, Jesus A1 - Meessen, Joachim A1 - Moritz, Sophie A1 - Moeller, Ralf A1 - Olsson-Francis, Karen A1 - Onofri, Silvano A1 - Ott, Sieglinde A1 - Pacelli, Claudia A1 - Podolich, Olga A1 - Rabbow, Elke A1 - Reitz, Günther A1 - Rettberg, Petra A1 - Reva, Oleg A1 - Rothschild, Lynn A1 - Garcia Sancho, Leo A1 - Schulze-Makuch, Dirk A1 - Selbmann, Laura A1 - Serrano, Paloma A1 - Szewzyk, Ulrich A1 - Verseux, Cyprien A1 - Wadsworth, Jennifer A1 - Wagner, Dirk A1 - Westall, Frances A1 - Wolter, David A1 - Zucconi, Laura T1 - Limits of life and the habitability of Mars BT - the ESA space experiment BIOMEX on the ISS T2 - Astrobiology N2 - BIOMEX (BIOlogy and Mars EXperiment) is an ESA/Roscosmos space exposure experiment housed within the exposure facility EXPOSE-R2 outside the Zvezda module on the International Space Station (ISS). The design of the multiuser facility supports-among others-the BIOMEX investigations into the stability and level of degradation of space-exposed biosignatures such as pigments, secondary metabolites, and cell surfaces in contact with a terrestrial and Mars analog mineral environment. In parallel, analysis on the viability of the investigated organisms has provided relevant data for evaluation of the habitability of Mars, for the limits of life, and for the likelihood of an interplanetary transfer of life (theory of lithopanspermia). In this project, lichens, archaea, bacteria, cyanobacteria, snow/permafrost algae, meristematic black fungi, and bryophytes from alpine and polar habitats were embedded, grown, and cultured on a mixture of martian and lunar regolith analogs or other terrestrial minerals. The organisms and regolith analogs and terrestrial mineral mixtures were then exposed to space and to simulated Mars-like conditions by way of the EXPOSE-R2 facility. In this special issue, we present the first set of data obtained in reference to our investigation into the habitability of Mars and limits of life. This project was initiated and implemented by the BIOMEX group, an international and interdisciplinary consortium of 30 institutes in 12 countries on 3 continents. Preflight tests for sample selection, results from ground-based simulation experiments, and the space experiments themselves are presented and include a complete overview of the scientific processes required for this space experiment and postflight analysis. The presented BIOMEX concept could be scaled up to future exposure experiments on the Moon and will serve as a pretest in low Earth orbit. KW - EXPOSE-R2 KW - BIOMEX KW - Habitability KW - Limits of life KW - Extremophiles KW - Mars Y1 - 2019 U6 - https://doi.org/10.1089/ast.2018.1897 SN - 1531-1074 SN - 1557-8070 VL - 19 IS - 2 SP - 145 EP - 157 PB - Liebert CY - New Rochelle ER - TY - JOUR A1 - Shayduk, Roman A1 - Hallmann, Jörg A1 - Rodriguez-Fernandez, Angel A1 - Scholz, Markus A1 - Lu, Wei A1 - Bösenberg, Ulrike A1 - Möller, Johannes A1 - Zozulya, Alexey A1 - Jiang, Man A1 - Wegner, Ulrike A1 - Secareanu, Radu-Costin A1 - Palmer, Guido A1 - Emons, Moritz A1 - Lederer, Max A1 - Volkov, Sergey A1 - Lindfors-Vrejoiu, Ionela A1 - Schick, Daniel A1 - Herzog, Marc A1 - Bargheer, Matias A1 - Madsen, Anders T1 - Femtosecond x-ray diffraction study of multi-THz coherent phonons in SrTiO3 JF - Applied physics letters N2 - We report generation of ultra-broadband longitudinal acoustic coherent phonon wavepackets in SrTiO3 (STO) with frequency components extending throughout the first Brillouin zone. The wavepackets are efficiently generated in STO using femtosecond infrared laser excitation of an atomically flat 1.6 nm-thick epitaxial SrRuO3 film. We use femtosecond x-ray diffraction at the European X-Ray Free Electron Laser Facility to study the dispersion and damping of phonon wavepackets. The experimentally determined damping constants for multi-THz frequency phonons compare favorably to the extrapolation of a simple ultrasound damping model over several orders of magnitude. Y1 - 2022 U6 - https://doi.org/10.1063/5.0083256 SN - 0003-6951 SN - 1077-3118 VL - 120 IS - 20 PB - AIP Publishing CY - Melville ER -