Learning through interaction and embodied practice in a scientific laboratory

textThis study purports to explore how apprentices in microbiology, through interaction and multimodal activities, acquire the knowledge and skills that are necessary for doing scientific experiments. It aims to examine the ways novices learn to scrutinize and discuss the data under investigation, how experts communicate scientific knowledge about microbes to novices, and how experts and novices together create new scientific knowledge during the apprenticeship. Furthermore, this study aims at explaining the various ways narratives contribute to the socialization of the apprentice into the workplace and the scientific field, and how stories help retain knowledge, gained in one situation, to be used in other contexts and situations. To achieve this aim, I videotaped daily activities in a small microbiology lab, focusing on detailed observations of experts and novices as they engaged in teaching and learning. I was especially interested in what kinds of innovative symbolic communication resources would be invoked during such educational activities. In addition, I collected data pertaining to how the apprentice was socialized into this particular community of practice. I applied a ‘situated learning’ approach to the analysis of the instructional data, as well as discourse analytic and social semiotic methods of analyzing verbal and nonverbal, embodied interaction. I found that researchers, by using embodied and semiotic resources, created moments of shared participation between themselves and their scientific objects. Likewise I found that gestures shaped objects and concepts, and brought these into an intersubjective space where researchers, tools, instruments, and concepts interacted in a collaborative architecture. I named the specific literacy prevalent in scientific experimentation (reading and understanding graphs, diagrams, pictures, etc.) as ‘science literacy’, to distinguish it from the term ‘scientific literacy’, a general understanding of popularized scientific topics. Blurred boundaries were discovered between the living organisms and their semiotic representations whenever the expert and the novice referred to the living organisms in their discussions concerning graphs and diagrams. The researchers changed their terminology, depending on the bacteria changing from animate to inanimate status. Finally, I discovered the significance of contextual tellability in narratives functioning both as introduction to the workplace and as memory devices.Anthropolog

Elastin organization in pig and cardiovascular disease patients' pericardial resistance arteries

Peripheral vascular resistance is increased in essential hypertension. This involves structural changes of resistance arteries and stiffening of the arterial wall, including remodeling of the extracellular matrix. We hypothesized that biopsies of the human parietal pericardium, obtained during coronary artery bypass grafting or cardiac valve replacement surgeries, can serve as a source of resistance arteries for structural research in cardiovascular disease patients. We applied two-photon excitation fluorescence microscopy to study the parietal pericardium and isolated pericardial resistance arteries with a focus on the collagen and elastin components of the extracellular matrix. Initial findings in pig tissue were confirmed in patient biopsies. The microarchitecture of the internal elastic lamina in both the pig and patient pericardial resistance arteries (studied at a transmural pressure of 100 mm Hg) is fiber like, and no prominent external elastic lamina could be observed. This microarchitecture is very different from that in rat mesenteric arteries frequently used for resistance artery research. In conclusion, we add three-dimensional information on the structure of the extracellular matrix in resistance arteries from cardiovascular disease patients and propose further use of patient pericardial resistance arteries for studies of the human microvasculature

Imaging and modeling of acute pressure-induced changes of collagen and elastin microarchitectures in pig and human resistance arteries

The impact of disease-related changes in the extracellular matrix (ECM) on the mechanical properties of human resistance arteries largely remains to be established. Resistance arteries from both pig and human parietal pericardium (PRA) display a different ECM microarchitecture compared with frequently used rodent mesenteric arteries. We hypothesized that the biaxial mechanics of PRA mirror pressure-induced changes in the ECM microarchitecture. This was tested using isolated pig PRA as a model system, integrating vital imaging, pressure myography, and mathematical modeling. Collagenase and elastase digestions were applied to evaluate the load-bearing roles of collagen and elastin, respectively. The incremental elastic modulus linearly related to the straightness of adventitial collagen fibers circumferentially and longitudinally (both R-2 &gt;= 0.99), whereas there was a nonlinear relationship to the internal elastic lamina elastin fiber branching angles. Mathematical modeling suggested a collagen recruitment strain (means +/- SE) of 1.1 +/- 0.2 circumferentially and 0.20 +/- 0.01 longitudinally, corresponding to a pressure of similar to 40 mmHg, a finding supported by the vital imaging. The integrated method was tested on human PRA to confirm its validity. These showed limited circumferential distensibility and elongation and a collagen recruitment strain of 0.8 +/- 0.1 circumferentially and 0.06 +/- 0.02 longitudinally, reached at a distending pressure below 20 mmHg. This was confirmed by vital imaging showing negligible microarchitectural changes of elastin and collagen upon pressurization. In conclusion, we show here, for the first time in resistance arteries, a quantitative relationship between pressure-induced changes in the extracellular matrix and the arterial wall mechanics. The strength of the integrated methods invites for future detailed studies of microvascular pathologies.NEW &amp; NOTEWORTHY This is the first study to quantitatively relate pressure-induced microstructural changes in resistance arteries to the mechanics of their wall. Principal findings using a pig model system were confirmed in human arteries. The combined methods provide a strong tool for future hypothesis-driven studies of microvascular pathologies.</p

Critical Discourse Analysis: Definition, Approaches, Relation to Pragmatics, Critique, and Trends

This chapter introduces the transdisciplinary research movement of critical discourse analysis (CDA) beginning with its definition and recent examples of CDA work. In addition, approaches to CDA such as the dialectical relational (Fairclough), sociocognitive (van Dijk), discourse historical (Wodak), social actors (van Leeuwen), and the Foucauldian dispositive analysis (Jager and Maier) are outlined, as well as the complex relation of CDA to pragmatics. Next, the chapter provides a brief mention of the extensive critique of CDA, the creation of critical discourse studies (CDS), and new trends in CDA, including positive discourse analysis (PDA), CDA with multimodality, CDA and cognitive linguistics, critical applied linguistics, and other areas (rhetoric, education, anthropology/ethnography, sociolinguistics, culture, feminism/gender, and corpus studies). It ends with new directions aiming towards social action for social justice