Investigating subject-specific writing skills and historical reasoning in historical explanations: a study of 7th- and 8th-grade comprehensive school students in North Rhine-Westphalia, Germany

The purpose of this study was to examine the writing skills of 7th- and 8th-grade students with a high proportion of migration background in North Rhine-Westphalia, Germany. The study was part of the SchriFT project (2017–20), funded by the Federal Ministry of Education and Research. A writing task was given on the topic: Why can we only make assumptions about many past events? As an answer to the task, the students had to write a historical explanation that took into account the epistemological principles of historical reasoning. The students’ writing was analysed using a category system, and their historical knowledge was assessed through a knowledge test. The results showed that the students possess diverse levels of writing skills, with few producing elaborate explanations, and most struggling with the subject-specific language and reasoning skills. The study also highlights the potential for genre-based writing approaches in history education. The results suggest that many students perceive history as an image of the past and have limited understanding of historical reasoning. Further research is needed to investigate the influence of motivation and interest on language learning

Blending systems thinking approaches for organisational analysis: reviewing child protection in England

This paper concerns the innovative use of a blend of systems thinking ideas in the ‘Munro Review of Child Protection’, a high-profile examination of child protection activities in England, conducted for the Department for Education. We go ‘behind the scenes’ to describe the OR methodologies and processes employed. The circumstances that led to the Review are outlined. Three specific contributions that systems thinking made to the Review are then described. First, the systems-based analysis and visualisation of how a ‘compliance culture’ had grown up. Second the creation of a large, complex systems map of current operations and the effects of past policies on them. Third, how the map gave shape to the range of issues the Review addressed and acted as an organising framework for the systemically coherent set of recommendations made. The paper closes with an outline of the main implementation steps taken so far to create a child protection system with the critically reflective properties of a learning organisation, and methodological reflections on the benefits of systems thinking to support organisational analysis

The Black Hole in the Compact, High-dispersion Galaxy NGC 1271

Located in the Perseus cluster, NGC 1271 is an early-type galaxy with a small effective radius of 2.2 kpc and a large stellar velocity dispersion of 276 km/s for its K-band luminosity of 8.9x10^{10} L_sun. We present a mass measurement for the black hole in this compact, high-dispersion galaxy using observations from the integral field spectrograph NIFS on the Gemini North telescope assisted by laser guide star adaptive optics, large-scale integral field unit observations with PPAK at the Calar Alto Observatory, and Hubble Space Telescope WFC3 imaging observations. We are able to map out the stellar kinematics on small spatial scales, within the black hole sphere of influence, and on large scales that extend out to four times the galaxy's effective radius. We find that the galaxy is rapidly rotating and exhibits a sharp rise in the velocity dispersion. Through the use of orbit-based stellar dynamical models, we determine that the black hole has a mass of (3.0^{+1.0}_{-1.1}) x 10^9 M_sun and the H-band stellar mass-to-light ratio is 1.40^{+0.13}_{-0.11} M_sun/L_sun (1-sigma uncertainties). NGC 1271 occupies the sparsely-populated upper end of the black hole mass distribution, but is very different from the Brightest Cluster Galaxies (BCGs) and giant elliptical galaxies that are expected to host the most massive black holes. Interestingly, the black hole mass is an order of magnitude larger than expectations based on the galaxy's bulge luminosity, but is consistent with the mass predicted using the galaxy's bulge stellar velocity dispersion. More compact, high-dispersion galaxies need to be studied using high spatial resolution observations to securely determine black hole masses, as there could be systematic differences in the black hole scaling relations between these types of galaxies and the BCGs/giant ellipticals, thereby implying different pathways for black hole and galaxy growth.Comment: accepted for publication in Ap

Photoionization models of the CALIFA HII regions. I. Hybrid models

Photoionization models of HII regions require as input a description of the ionizing SED and of the gas distribution, in terms of ionization parameter U and chemical abundances (e.g. O/H and N/O). A strong degeneracy exists between the hardness of the SED and U, which in turn leads to high uncertainties in the determination of the other parameters, including abundances. One way to resolve the degeneracy is to fix one of the parameters using additional information. For each of the ~ 20000 sources of the CALIFA HII regions catalog, a grid of photoionization models is computed assuming the ionizing SED being described by the underlying stellar population obtained from spectral synthesis modeling. The ionizing SED is then defined as the sum of various stellar bursts of different ages and metallicities. This solves the degeneracy between the shape of the ionizing SED and U. The nebular metallicity (associated to O/H) is defined using the classical strong line method O3N2 (which gives to our models the status of "hybrids"). The remaining free parameters are the abundance ratio N/O and the ionization parameter U, which are determined by looking for the model fitting [NII]/Ha and [OIII]/Hb. The models are also selected to fit [OII]/Hb. This process leads to a set of ~ 3200 models that reproduce simultaneously the three observations. We find that the regions associated to young stellar bursts suffer leaking of the ionizing photons, the proportion of escaping photons having a median of 80\%. The set of photoionization models satisfactorily reproduces the electron temperature derived from the [OIII]4363/5007 line ratio. We determine new relations between the ionization parameter U and the [OII]/[OIII] or [SII]/[SIII] line ratios. New relations between N/O and O/H and between U and O/H are also determined. All the models are publicly available on the 3MdB database.Comment: Accepted for publication in A&

The structural and dynamical properties of compact elliptical galaxies

Dedicated photometric and spectroscopic surveys have provided unambiguous evidence for a strong stellar mass-size evolution of galaxies within the last 10 Gyr. The likely progenitors of today's most massive galaxies are remarkably small, disky, passive and have already assembled much of their stellar mass at redshift z=2. An in-depth analysis of these objects, however, is currently not feasible due to the lack of high-quality, spatially-resolved photometric and spectroscopic data. In this paper, we present a sample of nearby compact elliptical galaxies (CEGs), which bear resemblance to the massive and quiescent galaxy population at earlier times. Hubble Space Telescope (HST) and wide-field integral field unit (IFU) data have been obtained, and are used to constrain orbit-based dynamical models and stellar population synthesis (SPS) fits, to unravel their structural and dynamical properties. We first show that our galaxies are outliers in the present-day stellar mass-size relation. They are, however, consistent with the mass-size relation of compact, massive and quiescent galaxies at redshift z=2. The compact sizes of our nearby galaxies imply high central stellar mass surface densities, which are also in agreement with the massive galaxy population at higher redshift, hinting at strong dissipational processes during their formation. Corroborating evidence for a largely passive evolution within the last 10 Gyr is provided by their orbital distribution as well as their stellar populations, which are difficult to reconcile with a very active (major) merging history. This all supports that we can use nearby CEGs as local analogues of the high-redshift, massive and quiescent galaxy population, thus providing additional constraints for models of galaxy formation and evolution.Comment: 33 pages, 27 figures and 20 tables (with most of the tables provided as online-only supporting information). Accepted for publication in MNRA

Efficient Parametrization of the Vertex Function, Ω\Omega-Scheme, and the (t,t')-Hubbard Model at Van Hove Filling

We propose a new parametrization of the four-point vertex function in the one-loop one-particle irreducible renormalization group (RG) scheme for fermions. It is based on a decomposition of the effective two-fermion interaction into fermion bilinears that interact via exchange bosons. The numerical computation of the RG flow of the boson propagators reproduces the leading weak coupling instabilities of the two-dimensional Hubbard model at Van Hove filling, as they were previously obtained by a temperature RG flow. Instead of regularizing with temperature, we here use a soft frequency $\Omega$-regularization that likewise does not artificially suppress ferromagnetism. Besides being more efficient than previous N-patch schemes, this parametrization also reduces the ambiguities in introducing boson fields.Comment: 33 pages, 11 figures, references adde

CD11b/CD18 mediates production of reactive oxygen species by mouse and human macrophages adherent to matrixes containing oxidized LDL

Production of reactive oxygen species (ROS) and other proinflammatory substances by macrophages adherent to matrix proteins that contain or have been modified by oxidized LDL (oxLDL) may play an important role in atherogenesis. In vitro, human macrophages adhere to matrixes containing oxLDL via scavenger receptors and are signaled to produce ROS partly by interactions of the class B scavenger receptor (SR-B) CD36 with ligands on the matrix. In this report, we show that macrophages from mice genetically deficient in SR-A or CD36 adhered equally as well and produced equal amounts of ROS on interaction with matrix-associated oxLDL. In contrast, macrophages from mice genetically deficient in the CD18 chain of β2-integrins produced insignificant amounts of ROS on interaction with oxLDL-containing matrixes, even though they adhered to these matrixes as efficiently as did macrophages from wild-type mice. Antibodies against CD18, CD11b, or EDTA, the last of which chelates divalent cations required for integrin function, had no effect on adhesion of normal mouse or human macrophages to matrixes containing oxLDL but almost completely inhibited ROS production by macrophages adherent to this matrix. Thus, CD11b/CD18 plays an important role in regulating production of ROS by mouse and human macrophages adherent to matrixes containing oxLDL. It may play a hitherto-unsuspected role in regulating macrophage signaling pathways involved in inflammation and atherogenesis

Recommendations for the engineering characterization of single-use bioreactors

Single-use bioreactors have been available for more than 15 years and are nowadays widely accepted for a broad range of applications. However, process engineering data for these bioreactors, including volumetric mass transfer coefficients, mixing times and power inputs, are still limited. Furthermore, these data are often generated using a number of different methods, making comparisons difficult. In addition, the large variety of bioreactor types and their mixing principles (stirred, wave-mixed, orbitally-shaken, etc.) increases the difficulty in comparing the engineering data. In order to facilitate the usage of single-use bioreactors, the DECHEMA Upstream Processing (USP) expert group on ‘Single-use technology in biopharmaceutical manufacturing’ has developed recommendations for the process engineering characterization of single-use bioreactors. The methods are based on procedures that were previously developed for multi-use bioreactors and were tested in universities as well as companies (both from the supplier and user sides) for their robustness. The validated recommendations now include measurements of volumetric mass transfer coefficient, mixing time and power input. These parameters are experimentally determined using the dynamic gassing-out method, the decolorization method or sensor method, and the torque method respectively. The poster gives an overview of the fundamentals and procedures of the methods applied, and current results from the interlaboratory tests. Recent foci include the measurement of carbon dioxide gas-liquid mass transfer and the determination of mechanical stress due to hydrodynamics