Desalination of masonry structures: Fine tuning of pore size distribution of poultices to substrate properties

Desalination is a relatively new intervention in the field of conservation of architectural heritage. Especially the desalination of immovable objects, such as masonry structures, is still a trial-error practice. In the field, different desalination materials and methods are used, sometimes with unsatisfactory results. Better understanding of the desalination process is needed in order to support the conservator with clear guidelines for choosing a suitable desalination material and method. The research presented in this paper constitutes the first step towards the development of a modular system of poultices, which can be adapted, i.e. fine-tuned to different types of substrates. Starting point is to make use of advection, i.e. the transport of salt ions with water flow. This transport mechanism is faster than diffusion and the application on immovable objects is relatively easy. In order to optimize salt extraction, a poultice working by advection should have smaller pores than the substrate. Starting from this principle the pore sizes of different desalination materials (sand, cellulose, kaolin and bentonite) mixed in different proportions, have been measured. Interesting results were obtained, showing that the desalination materials commonly used in the field are often not the most suitable ones. On the basis of the results, recipes for poultices, adapted to a specific substrate, can be formulated.     

Practical Applications as a Source of Credibility: A Comparison of Three Fields of Dutch Academic Chemistry

In many Western science systems, funding structures increasingly stimulate academic research to contribute to practical applications, but at the same time the rise of bibliometric performance assessments have strengthened the pressure on academics to conduct excellent basic research that can be published in scholarly literature. We analyze the interplay between these two developments in a set of three case studies of fields of chemistry in the Netherlands. First, we describe how the conditions under which academic chemists work have changed since 1975. Second, we investigate whether practical applications have become a source of credibility for individual researchers. Indeed, this turns out to be the case in catalysis, where connecting with industrial applications helps in many steps of the credibility cycle. Practical applications yield much less credibility in environmental chemistry, where application-oriented research agendas help to acquire funding, but not to publish prestigious papers or to earn peer recognition. In biochemistry practical applications hardly help in gaining credibility, as this field is still strongly oriented at fundamental questions. The differences between the fields can be explained by the presence or absence of powerful upstream end-users, who can afford to invest in academic research with promising long term benefits.     

Virology Experts in the Boundary Zone Between Science,Policy and the Public: A Biographical Analysis

This article aims to open up the biographical black box of three experts working in the boundary zone between science, policy and public debate. A biographical-narrative approach is used to analyse the roles played by the virologists Albert Osterhaus, Roel Coutinho and Jaap Goudsmit in policy and public debate. These figures were among the few leading virologists visibly active in the Netherlands during the revival of infectious diseases in the 1980s. Osterhaus and Coutinho in particular are still the key figures today, as demonstrated during the outbreak of novel influenza A (H1N1). This article studies the various political and communicative challenges and dilemmas encountered by these three virologists, and discusses the way in which, strategically or not, they handled those challenges and dilemmas during the various stages of the field’s recent history. Important in this respect is their pursuit of a public role that is both effective and credible. We will conclude with a reflection on the H1N1 pandemic, and the historical and biographical ties between emerging governance arrangements and the experts involved in the development of such arrangements.     

Neuroanatomy Learning: Augmented Reality vs. Cross-Sections

Neuroanatomy education is a challenging field which could benefit from modern innovations, such as augmented reality (AR) applications. This study investigates the differences on test scores, cognitive load, and motivation after neuroanatomy learning using AR applications or using cross-sections of the brain. Prior to two practical assignments, a pretest (extended matching questions, double-choice questions and a test on cross-sectional anatomy) and a mental rotation test (MRT) were completed. Sex and MRT scores were used to stratify students over the two groups. The two practical assignments were designed to study (1) general brain anatomy and (2) subcortical structures. Subsequently, participants completed a posttest similar to the pretest and a motivational questionnaire. Finally, a focus group interview was conducted to appraise participants’ perceptions. Medical and biomedical students (n = 31); 19 males (61.3%) and 12 females (38.7%), mean age 19.2 ± 1.7 years participated in this experiment. Students who worked with cross-sections (n = 16) showed significantly more improvement on test scores than students who worked with GreyMapp-AR (P = 0.035) (n = 15). Further analysis showed that this difference was primarily caused by significant improvement on the cross-sectional questions. Students in the cross-section group, moreover, experienced a significantly higher germane (P = 0.009) and extraneous cognitive load (P = 0.016) than students in the GreyMapp-AR group. No significant differences were found in motivational scores. To conclude, this study suggests that AR applications can play a role in future anatomy education as an add-on educational tool, especially in learning three-dimensional relations of anatomical structures.     

Strapping rowers to their sliding seat improves performance during the start of ergometer rowing

Abstract

Rowers sit on a seat that slides relative to the boat/ergometer. If a rower lifts him or herself from this sliding seat at any time, the seat will move away from under them and the rowing action is disrupted. From a mechanical perspective, it is clear that the need for the rower to remain in contact with the sliding seat at all times imposes position-dependent constraints on the forces exerted at the oar handle and the footstretcher. Here we investigate if the mechanical power output during rowing, which is strongly related to these forces, might be improved if the contact with the sliding seat was of no concern to the rower. In particular, we examine if elimination of these constraints by strapping the rower to the sliding seat leads to an increase in performance during the start on a standard rowing ergometer. Eleven well-trained female rowers performed 5-stroke starts in normal and strapped conditions. Handle force, vertical seat force, footstretcher force, and handle kinematics were recorded, from which mechanical power and work output were calculated. Most of the relevant mechanical variables differed significantly between the normal and strapped conditions. Most importantly, mechanical power output (averaged over the 5-stroke start) in the strapped condition was 12% higher than in the normal condition. We conclude that strapping a rower's pelvis to the sliding seat allows more vigorous execution of the stroke phases, resulting in a substantial improvement in performance during the start of ergometer rowing.     

Longitudinal retention of anatomical knowledge in second‐year medical students

The Radboud University Medical Center has a problem‐based, learner‐oriented, horizontally, and vertically integrated medical curriculum. Anatomists and clinicians have noticed students’ decreasing anatomical knowledge and the disability to apply knowledge in diagnostic reasoning and problem solving. In a longitudinal cohort, the retention of anatomical knowledge gained during the first year of medical school among second‐year medical students was assessed. In May 2011, 346 medical students applied for the second‐year gastro‐intestinal (GI) tract course. The students were asked to participate in a reexamination of a selection of anatomical questions of an examination from October 2009. The examination consisted of a clinical anatomy case scenario and two computed tomography (CT) images of thorax and abdomen in an extended matching format. A total of 165 students were included for analysis. In 2011, students scored significantly lower for the anatomy examination compared to 2009 with a decline in overall examination score of 14.7% (±11.7%). Decrease in knowledge was higher in the radiological questions, compared to the clinical anatomy cases 17.5% (±13.6%) vs. 7.9% (±10.0%), respectively, d = 5.17. In both years, male students scored slightly better compared to female students, and decline of knowledge seems somewhat lower in male students (13.1% (±11.1%) vs. 15.5% (±12.0%), respectively), d = ?0.21. Anatomical knowledge in the problem‐oriented horizontal and vertical integrated medical curriculum, declined by approximately 15% 1.5 year after the initial anatomy course. The loss of knowledge in the present study is relative small compared to previous studies. Anat Sci Educ 10: 242–248. © 2016 American Association of Anatomists.     

Preschool children's exposure to story grammar elements during parent–child book reading

Twenty‐three preschool‐age children, 3;6 (years; months) to 4;1, were videotaped separately with their mothers and fathers while each mother and father read a different unfamiliar storybook to them. The text from the unfamiliar storybooks was parsed and coded into story grammar elements and all parental extratextual utterances were transcribed and coded for (1) their relationship to the story grammar elements found within the storybook, and (2) the natural strategies parents used to direct their children's attention to these elements. Children's overall exposure to story grammar elements during book reading was also explored for its relationship to their language abilities. Results indicated that parents focused significantly more on the resolution, attempt, and consequence compared to the initiating event and plan, and most frequently used the text and pictures as strategies for recruiting their children's attention to the story grammar elements within the book. In addition, the frequency of parental utterances related to story grammar elements was negatively correlated with children's language abilities. This study did not examine the complexity or depth of parental utterances related to story grammar elements. These findings provide initial evidence that children may derive their understanding of story grammar at least in part through their parents' extratextual discussions during parent–child book reading.     

Positive teacher–student relationships go beyond the classroom,problematic ones stay inside

The authors voice teachers' perceptions of their interpersonal experiences with students in both positive and problematic relationships. Interview data from 28 teachers were examined by coding utterances on teacher and student interactions. Results indicate that teachers defined the quality of the relationship mostly by the level of communion (friendly vs. hostile), instead of by the level of agency (in control vs. powerless). Analyses of mentioned teacher and student behavior show a friendly interactional pattern for positive relationships and a hostile pattern for problematic ones. In teachers' perceptions, positive and problematic relationships also differed in context where encounters take place and topic of talk. Contrary to interactions in problematic relationships, encounters in positive relationships were mostly situated outside the classroom context and conversations during these encounters covered a wide range of topics. Implications for teacher education programs are discussed.     

Should professional development include analyzing and coaching ways of speaking during inquiry-based science instruction in elementary classrooms?

In this commentary, I first consider what Oliveira defines inquiry-based science instruction to be. Next I discuss what the discourse practices are that he is advocating. Then I examine what he presents as evidence of changes in two teachers’ discourse practices due to a summer institute and how their pragmatic awareness seems to have been enhanced through institute activities. Finally I ponder whether, when, how, and why professional development should include a focus on ways of speaking during inquiry-based science instruction.     

Online discussion compensates for suboptimal timing of supportive information presentation in a digitally supported learning environment

This study used a sequential set-up to investigate the consecutive effects of timing of supportive information presentation (information before vs. information during the learning task clusters) in interactive digital learning materials (IDLMs) and type of collaboration (personal discussion vs. online discussion) in computer-supported collaborative learning (CSCL) on student knowledge construction. Students (N = 87) were first randomly assigned to the two information presentation conditions to work individually on a case-based assignment in IDLM. Students who received information during learning task clusters tended to show better results on knowledge construction than those who received information only before each cluster. The students within the two separate information presentation conditions were then randomly assigned to pairs to discuss the outcomes of their assignments under either the personal discussion or online discussion condition in CSCL. When supportive information had been presented before each learning task cluster, online discussion led to better results than personal discussion. When supportive information had been presented during the learning task clusters, however, the online and personal discussion conditions had no differential effect on knowledge construction. Online discussion in CSCL appeared to compensate for suboptimal timing of presentation of supportive information before the learning task clusters in IDLM.