How Things Matter in Everyday Lives of Preschool Age Children: Material-Semiotic Investigations in Psychology and Education

This article draws on materials from ethnographic and participatory research on everyday eating practices in Berlin kindergartens. It argues that agency is not al- ways a-priori located in the human subject. Agency can be translated and distri- buted over relational networks that include people and things; it can even be left over to things depending on the constellation in question. A material-semiotic approach is thus outlined that pays attention to micro-configurations and closely explores action – a focus which can further advance psychological theory and methodology

Eating in the Nursery School: Pedagogy, Performativity & Biopolitics

The study presented here explores eating as a pedagogical practice. It pays attention to arrangements of things such as Christmas cookies, whole-wheat and white bread, frozen chicken, plates, chairs, tables, and freezers. Entering in dialogue with performativity theory and post-structuralist approaches, a series of ethnographic analyses from German and Brazilian nursery schools reveal how eating can be enacted as a sensual pleasure, a health risk, an ethnic custom, or a civil right within a variety of local pedagogical contexts. Through specific arrangements of foods and other things, young children are educated to eat with moderation, to change their ethnic dietary habits, or to become modern citizens. Pedagogy can thus entail doing public health, doing ethnic identity, or doing citizenship while eating is an important way of doing these in early childhood education and care settings

Eating Christmas Cookies, Whole-wheat Bread and Frozen Chicken in the Kindergarten: Doing Pedagogy by Other Means

The study presented here explores eating as a pedagogical practice by paying attention to arrangements of things such as Christmas cookies, whole-wheat and white bread, frozen chicken, plates, chairs, tables, and freezers. Through a series of ethnographic research examples from German and Brazilian preschools, it investigates how eating in the kindergarten can be a sensual pleasure, a health risk, an ethnic custom, or a civil right within different local histories. Through specific arrangements of foods and other things, young children are educated to eat with moderation, to change their ethnic dietary habits, or to be "modern citizens". Pedagogy can thus consist of doing public health, doing ethnic identity, or doing citizenship. Eating is an important way of doing pedagogy in early childhood education and care settings. © 2013 Springer Fachmedien Wiesbaden

Cultural-historical Activity Theory Travels to Greece: Actors, Contexts and Politics of Reception and Interpretation

This article explores how socio-cultural, cultural-historical and activity theory approaches to education and psychology have traveled to Greece over the last three decades. It explores the history of introducing these approaches in the Greek context while identifying key dimensions of the process, such as: diverse interpretation of original works, key actors in academic teaching and research and linkages with educational policy and activism beyond the university spaces. Greece with its specific history of military dictatorship, constitutional change, varied struggles for democracy within the university, European integration, and current crisis and neoliberal reforms is seen as a sample case; taking this case as a point of departure, the authors develop a meta-theoretical frame on how to discuss the various ways in which socio-cultural-historical approaches have traveled across socio-cultural, historical, institutional, political, regional, and also, increasingly globalized contexts of education

Online Groups in Educational Settings: An Opportunity for Argumentation

The aim of this paper is to explore how students and teachers used posts in five groups on Facebook and how argumentation emerged as a communicative activity. For understanding such argumentative process, this study is framed in the Cultural Historical Activity Theory (CHAT), with a methodological perspective that enables the participants to act as co-authors of the intervention design. We draw our data from the posts inside five groups of teacher-students on Facebook, from February/2013 to June/2014, which were analysed qualitatively, considering discursive and linguistic aspects of the posts. Our findings pointed out that in situation in which collaboration occurred among students, there was a transition from authoritative discourse to internally persuasive discourse in the posts with argumentative indicators

Discovery of X-ray polarization angle rotation in active galaxy Mrk 421

The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can track how the magnetic field changes in the flow of the radiating particles by observing rotations of the electric vector position angle $\Psi$. Here we report the discovery of a $\Psi_{\mathrm x}$ rotation in the X-ray band in the blazar Mrk 421 at an average flux state. Across the 5 days of Imaging X-ray Polarimetry Explorer (IXPE) observations of 4-6 and 7-9 June 2022, $\Psi_{\mathrm x}$ rotated in total by $\geq360^\circ$. Over the two respective date ranges, we find constant, within uncertainties, rotation rates ($80 \pm 9$ and $91 \pm 8 ^\circ/\rm day$) and polarization degrees ($\Pi_{\mathrm x}=10\%\pm1\%$). Simulations of a random walk of the polarization vector indicate that it is unlikely that such rotation(s) are produced by a stochastic process. The X-ray emitting site does not completely overlap the radio/infrared/optical emission sites, as no similar rotation of $\Psi$ was observed in quasi-simultaneous data at longer wavelengths. We propose that the observed rotation was caused by a helical magnetic structure in the jet, illuminated in the X-rays by a localized shock propagating along this helix. The optically emitting region likely lies in a sheath surrounding an inner spine where the X-ray radiation is released

Magnetic Field Properties inside the Jet of Mrk 421: Multiwavelength Polarimetry Including the Imaging X-ray Polarimetry Explorer

We conducted a polarimetry campaign from radio to X-ray wavelengths of the high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry Explorer (IXPE) measurements on 2022 December 6-8. We detected X-ray polarization of Mrk 421 with a degree of $\Pi_{\rm X}$=14$\pm$1$\%$ and an electric-vector position angle $\psi_{\rm X}$=107$\pm$3$^{\circ}$ in the 2-8 keV band. From the time variability analysis, we find a significant episodic variation in $\psi_{\rm X}$. During 7 months from the first IXPE pointing of Mrk 421 in 2022 May, $\psi_{\rm X}$ varied across the range of 0$^{\circ}$ to 180$^{\circ}$, while $\Pi_{\rm X}$ maintained similar values within $\sim$10-15$\%$. Furthermore, a swing in $\psi_{\rm X}$ in 2022 June was accompanied by simultaneous spectral variations. The results of the multiwavelength polarimetry show that the X-ray polarization degree was generally $\sim$2-3 times greater than that at longer wavelengths, while the polarization angle fluctuated. Additionally, based on radio, infrared, and optical polarimetry, we find that rotation of $\psi$ occurred in the opposite direction with respect to the rotation of $\psi_{\rm X}$ over longer timescales at similar epochs. The polarization behavior observed across multiple wavelengths is consistent with previous IXPE findings for HSP blazars. This result favors the energy-stratified shock model developed to explain variable emission in relativistic jets. The accompanying spectral variation during the $\psi_{\rm X}$ rotation can be explained by a fluctuation in the physical conditions, e.g., in the energy distribution of relativistic electrons. The opposite rotation direction of $\psi$ between the X-ray and longer-wavelength polarization accentuates the conclusion that the X-ray emitting region is spatially separated from that at longer wavelengths.Comment: 17 pages, 13 figures, 4 tables; Accepted for publication in A&

X-ray Polarization Observations of BL Lacertae

Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus the Synchrotron emission to be responsible for the low frequency peak, while the origin of the high frequency hump is still debated. The analysis of X-rays and their polarization can provide a valuable tool to understand the physical mechanisms responsible for the origin of high-energy emission of blazars. We report the first observations of BL Lacertae performed with the Imaging X-ray Polarimetry Explorer ({IXPE}), from which an upper limit to the polarization degree $\Pi_X<$12.6\% was found in the 2-8 keV band. We contemporaneously measured the polarization in radio, infrared, and optical wavelengths. Our multiwavelength polarization analysis disfavors a significant contribution of proton synchrotron radiation to the X-ray emission at these epochs. Instead, it supports a leptonic origin for the X-ray emission in BL Lac.Comment: 17 pages, 5 figures, accepted for publication in ApJ