The development of the concept of atoms and molecules Dalton and beyond

The concept that all matter is made up of atoms was suggested by Dalton in 1803. It was a very useful concept, which could explain many of the experimental observations, but people were sceptical and considered atoms to be hypothetical objects until the beginning of the 20th century. By the end of the 20th century, advances in science and technology led to imaging of atoms and molecules. Now we are in a position to actually ‘see’ them using the scanning probe microscopies.     

How to improve argumentation comprehension in university students: experimental test of a training approach

Instructional Science - The ability to comprehend informal arguments is essential for scientific literacy but students often lack structural knowledge about these arguments, especially when the...     

Academic Libraries and Autism Spectrum Disorder: What Do We Know?

This paper examines the rising rates of autism spectrum disorder (ASD) in children in the United States (1 in 59), and explores the role academic libraries can play in helping college students with ASD. A literature review of how different types of libraries (school, public, academic) support students with ASD indicates research in this area in general is lacking. Findings point to lack of adequate training and awareness for librarians and staff, resources, services and spaces are universal challenges. Several initiatives that academic libraries and librarians may consider in helping students with ASD are identified and described.     

Biomechanische Grundlagen des Startsprungs im Schwimmen

Starting block performance in swimming is of crucial importance in the individual competitions for the shorter swimming distances as well as for the relay events. The significance of this swim start performance will increase with the introduction of a new starting block with a longer and slightly steeper surface in conjunction with a push-off support for the feet and laterally adjustable handles. As grab starts and track starts were equally observed in international swimming competitions there are good reasons to assume that only the latter will remain the dominant starting technique. This report aims to summarize existing knowledge on the biomechanics of the swim start performed on a traditional starting block as a new starting block is introduced and new starting techniques are going to be developed. Following some introductory remarks on the assessment of the swim start performance, results will be discussed on the merit of different take-off techniques, on the entry behaviour, and on the force development profiles on the starting block. In conclusion, a tendency in favour of the rear-weighted track start was found in conjunction with a flat entry. In addition, it could be shown that an angular momentum around the transverse body axis combined with a dolphin kick (and a previously hyperextended hip joint) may provide hydrodynamic conditions to enter the water with a rather steep centre of mass trajectory. Finally, existing biomechanical knowledge will be presented on the relay start as well as on a possible change in the starting technique using the new block.     

Self-rated competences questionnaires from a design perspective

This paper provides a theoretical review of self-rated competences questionnaires. This topic is influenced by the ongoing world-wide reform of higher education, which has led to a focus on the learner outcomes of higher education. Consequently, questionnaires on self-rated competences have increasingly been employed. However, self-ratings are often criticised for their lack of validity. Our intention is to outline some principles of good questionnaire design and to use these principles to contrast questionnaires on self-rated competences. We begin with an overview of research about questionnaire design. Then we introduce seven questionnaires and portray them in terms of their design characteristics. A comparison reveals some significant points: biographical data need to be handled more carefully, and there is an overuse of vague and abstract language. On the positive side, all of the questionnaires that were examined provide reliable sub-scales covering important facets of competences.     

Long-term microfluidic glucose and lactate monitoring in hepatic cell culture

Monitoring cellular bioenergetic pathways provides the basis for a detailed understanding of the physiological state of a cell culture. Therefore, it is widely used as a tool amongst others in the field of in vitro toxicology. The resulting metabolic information allows for performing in vitro toxicology assays for assessing drug-induced toxicity. In this study, we demonstrate the value of a microsystem for the fully automated detection of drug-induced changes in cellular viability by continuous monitoring of the metabolic activity over several days. To this end, glucose consumption and lactate secretion of a hepatic tumor cell line were continuously measured using microfluidically addressed electrochemical sensors. Adapting enzyme-based electrochemical flat-plate sensors, originally designed for human whole-blood samples, to their use with cell culture medium supersedes the common manual and laborious colorimetric assays and off-line operated external measurement systems. The cells were exposed to different concentrations of the mitochondrial inhibitor rotenone and the cellular response was analyzed by detecting changes in the rates of the glucose and lactate metabolism. Thus, the system provides real-time information on drug-induced liver injury in vitro.     

Differently structured advance organizers lead to different initial schemata and learning outcomes

Does the specific structure of advance organizers influence learning outcomes? In the first experiment, 48 psychology students were randomly assigned to three differently structured advance organizers: a well-structured, a well-structured and key-concept emphasizing, and a less structured advance organizer. These were followed by a sorting task, a text study phase, and a posttest. The results indicated that differently structured advance organizers lead to different proto-schemata before and different learning outcomes after the text study phase. The second experiment replicated and extended these findings with 53 mathematics students. As in experiment 1, three differently structured advance organizers were used; but to rule out alternative explanations, the sorting task between the advance organizer and the text study phase was omitted. The results showed strong beneficial effects of well-structured advance organizers on near and far transfer tasks. Taken together, both experiments support the claim that the structure of advance organizers has an effect on preliminary schemata and learning outcomes. On a general level, the results indicate that advance organizers can support the generation of proto-schemata and thus can be more than the activation of “existing” concepts in long-term memory. With regard to education, this implies that educators should not only think about whether prior domain-specific knowledge is present, but also about how to scaffold the generation of proto-schemata at the beginning of instruction.