Why Do Historical Beeswax Seals Become Brittle Over Time?

ABSTRACT

Mechanical properties of aged beeswax were studied by an indirect measurement, using hydrogenated beeswax as a model material. The adequacy of the model was evaluated by comparison of its chemical composition and thermal properties with those of samples of historical beeswax. It was found that the gradual decrease in content of unsaturated compounds in beeswax contributes significantly to changes of its mechanical properties. As a consequence, beeswax artefacts become increasingly prone to mechanical damage during natural ageing. Understanding the difference between mechanical properties of recent and historical beeswax is primarily important from the point of view of safe handling and storage of such artefacts. Besides, this knowledge could help conservation scientists, e. g. when preparing model samples for testing new conservation methods.     

Study on surface properties of PDMS microfluidic chips treated with albumin

Electrokinetic properties and morphology of PDMS microfluidic chips intended for bioassays are studied. The chips are fabricated by a casting method followed by polymerization bonding. Microchannels are coated with 1% solution of bovine serum albumin (BSA) in Tris buffer. Albumin passively adsorbs on the PDMS surface. Electrokinetic characteristics (electro-osmotic velocity, electro-osmotic mobility, and zeta potential) of the coated PDMS channels are experimentally determined as functions of the electric field strength and the characteristic electrolyte concentration. Atomic force microscopy (AFM) analysis of the surface reveals a “peak and ridge” structure of the protein layer and an imperfect substrate coating. On the basis of the AFM observation, several topologies of the BSA-PDMS surface are proposed. A nonslip mathematical model of the electro-osmotic flow is then numerically analyzed. It is found that the electrokinetic characteristics computed for a channel with the homogeneous distribution of a fixed electric charge do not fit the experimental data. Heterogeneous distribution of the fixed electric charge and the surface roughness is thus taken into account. When a flat PDMS surface with electric charge heterogeneities is considered, the numerical results are in very good agreement with our experimental data. An optimization analysis finally allowed the determination of the surface concentration of the electric charge and the degree of the PDMS surface coating. The obtained findings can be important for correct prediction and possibly for robust control of behavior of electrically driven PDMS microfluidic chips. The proposed method of the electro-osmotic flow analysis at surfaces with a heterogeneous distribution of the surface electric charge can also be exploited in the interpretation of experimental studies dealing with protein-solid phase interactions or substrate coatings.     

Action research through lesson study for the reconstruction of teachers’ practical knowledge. A review of research at Málaga University (Spain)

ABSTRACT

This article aims to set out our discussions, reflections and research at Málaga University (Spain) in relation to Lesson Study (LS), as a cooperative action research process. The paper aims to summarise the main findings of ten years of research, addressing the concepts and dilemmas found both in forming teachers’ practical thinking and in the complex processes of reconstruction through LS. The results of our research provide evidence that it is a useful way to deal with the reconstruction of teachers’ practical knowledge in teacher training. Teachers’ practical knowledge should be more broadly seen as an active combination of theoretical knowledge, procedural knowledge and skills, attitudes, emotions, believes, and values: i.e. teachers’ practical thinking. Most of these personal and professional resources are unconscious, or rather sub-conscious. Changes in teachers’ practical thinking require more practical experience and reflexion: a dialectical process based around two key components: theorisation of practice and experimentation of reconstructed theory. The results of our research show that these dialectical process could be developed with LS as a particular way of developing AR, adding a complex, systematic, flexible and cooperative way of dealing with specific and contextual curricular innovation projects. We therefore conclude that LS could be a very useful path to follow in reconstructing teachers’ practical thinking from within, strengthening the professional teaching community.     

Formative assessment in mathematics for engineering students

In this paper, we present a range of formative assessment types for engineering mathematics, including in-class exercises, homework, mock examination questions, table quizzes, presentations, critical analyses of statistical papers, peer-to-peer teaching, online assessments and electronic voting systems. We provide practical tips for the implementation of such assessments, with a particular focus on time or resource constraints and large class sizes, as well as effective methods of feedback. In addition, we consider the benefits of such formative assessments for students and staff.     

Students’ Views on Difficulties in Learning Histology

The aim of this study was to provide a better understanding of the main difficulties hindering undergraduate biology students in learning histology. The study utilized a self-administered questionnaire which included three closed-ended and two open-ended questions: (1) if students had difficulty in learning about each tissue type; (2) what might be the problem in learning about the tissue at hand; (3) which topics were the most difficult; (4) what were the possible reasons that made image identification of tissue types difficult; and (5) how to improve the course curriculum from a student perspective. The survey was administered to 139 undergraduate biology students enrolled in a histology course, of which 101 surveys were completed and analyzed both qualitatively and quantitatively. The topics that students experienced the most difficulties with were: nervous tissue, plant tissues, bone tissues, and glandular epithelial tissue. The main reasons students experienced difficulties with these tissue types, according to the students themselves, were the nature of the topic, grasping the terminology used, and insufficient teaching time. Students suggested the adoption of strategies such as: teaching based on practical tasks; reducing the content of the histology curriculum; adding anatomy subjects; and making histology education more interesting.     

International Approaches to Whole-of-School Physical Activity Promotion

Increasing physical activity opportunities in schools has emerged as a global priority among school-aged youth. As a result, many countries have designed and implemented whole-of-school physical activity initiatives that seek to increase physical activity opportunities that are available to school-aged children before, during, and after school. Considering the comprehensive school physical activity program conceptual framework, this article includes a discussion of the initiatives from four countries: Finland (Finnish Schools on the Move), Ireland (Active School Flag), Poland (PE with Class), and the United States (Let’s Move Active Schools). Background information, implementation strategies, best practices, development opportunities, and relevant research from each country will be presented. Exploring different perspectives sheds some light on the international landscape relative to whole-of-school physical activity promotion and provides direction for future and continued research and practice.     

Implementation fidelity of a program designed to promote personal and social responsibility through physical education: a comparative case study

The purpose of this qualitative comparative case study was to examine the implementation fidelity of a program designed to deliver the Teaching Personal and Social Responsibility (TPSR) model (Hellison, 2003) through physical education and its relationship with short-term outcomes for elementary school students. The research questions were: (a) was the program implemented with fidelity, and (b) did better fidelity yield better student outcomes. Thus, we conducted a study on the implementation process used by two teachers who delivered the same program in two physical education classes in two different elementary schools in Spain. Data sources included observations and interviews with teachers and nonparticipant observers. Findings indicated that fidelity of implementation in Case 1 was higher and most children in those classes acquired the first three of five TPSR responsibility levels. Implementation fidelity in Case 2 was weaker and achievement of responsibility goals was minimal (only the first of five levels) and less stable for those students. This study is the first to directly examine the connection between TPSR implementation fidelity and student outcomes.     

Primary school teachers as a tool of secularisation of society in communist Czechoslovakia

This study focuses on the secularisation of society in communist Czechoslovakia (1948–1989) as a process in which primary school teachers played an important role. It aims to describe and explain typical everyday situations in which teachers were forced to fulfil tasks in connection with the Communist Party’s politics of secularisation. The text is based on witness memories obtained through oral history interviews, and on examination of historical archival sources and legislation. The study shows that the situations in which teachers found themselves in connection with performing these tasks were often not easy to face. This was, on the one hand, due to the expectations of the political establishment that teachers would obey their instructions meticulously and without reservations. The teachers, on the other hand, strove to interfere in negative ways with the lives of their students (and their families) as little as possible.     

Emergent curriculum in basic education for the new normality in Peru: orientations proposed from mathematics education

Educational Studies in Mathematics - The Peruvian basic education and its curriculum have been impacted by the COVID-19 pandemic. As a result, certain trends and phenomena have emerged, which shape...