Probing the AGN Unification Model at redshift z ∼\sim 3 with MUSE observations of giant Lyα\alpha nebulae

A prediction of the classic active galactic nuclei (AGN) unification model is the presence of ionisation cones with different orientations depending on the AGN type. Confirmations of this model exist for present times, but it is less clear in the early Universe. Here, we use the morphology of giant Ly$\alpha$ nebulae around AGNs at redshift z$\sim$3 to probe AGN emission and therefore the validity of the AGN unification model at this redshift. We compare the spatial morphology of 19 nebulae previously found around type I AGNs with a new sample of 4 Ly$\alpha$ nebulae detected around type II AGNs. Using two independent techniques, we find that nebulae around type II AGNs are more asymmetric than around type I, at least at radial distances $r>30$~physical kpc (pkpc) from the ionizing source. We conclude that the type I and type II AGNs in our sample show evidence of different surrounding ionising geometries. This suggests that the classical AGN unification model is also valid for high-redshift sources. Finally, we discuss how the lack of asymmetry in the inner parts (r$\lesssim$30 pkpc) and the associated high values of the HeII to Ly$\alpha$ ratios in these regions could indicate additional sources of (hard) ionizing radiation originating within or in proximity of the AGN host galaxies. This work demonstrates that the morphologies of giant Ly$\alpha$ nebulae can be used to understand and study the geometry of high redshift AGNs on circum-nuclear scales and it lays the foundation for future studies using much larger statistical samples.Comment: 15 pages, 13 figures, accepted for publication in MNRA

A Framework for Teaching Computational Thinking in Primary Schools: A Namibian Case Study

Several professional development programs have been designed to train in-service teachers on a computational thinking (CT) curriculum, but few researchers have examined how these affect primary school teachers\u27 self-efficacy and knowledge of CT in emerging economies. This study\u27s objective was to create a framework for the professional development of primary school in-service teachers for the teaching of CT (referred to as professional development for primary computational thinking - PD4PCT) to be integrated into teachers\u27 professional development programs. An initial framework was refined after implementing it at a Namibian school with a group of 14 teachers from five different disciplines (social studies, English, natural science, mathematics, and Afrikaans). Literature reviews, pre- and post-intervention questionnaires, semi-structured interviews, and self-reporting diaries were used to collect data. The framework was evaluated by experts via an online questionnaire. The findings show that teachers who participated in the professional development program improved their perceived CT knowledge, beliefs, and confidence to teach CT

Lineage Divergence and Historical Gene Flow in the Chinese Horseshoe Bat (Rhinolophus sinicus)

PMCID: PMC3581519This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Trading oxygen for iron:I. the [O/Fe]-specific star formation rate relation of galaxies

Our current knowledge of the star-forming metallicity of galaxies relies primarily on gas-phase oxygen abundance measurements. However, these do not always allow an accurate description of differences in stellar evolution and feedback, which are driven by variations in iron abundance. α-elements (such as oxygen) and iron are produced by sources that operate on different timescales and the link between them is not straightforward. We explore the origin of the [O/Fe]-specific SFR (sSFR) relation, linking chemical abundances to galaxy formation timescales. This relation is adhered to by star-forming galaxies across redshifts according to cosmological simulations and basic theoretical expectations. Its apparent universality makes it suitable for trading the readily available oxygen for iron abundance. We show that the relation is determined by the relative iron production efficiency of core-collapse and type Ia supernovae and the delay-time distribution of the latter-uncertain factors that could be constrained empirically with the [O/Fe]-sSFR relation. We compile and homogenise a literature sample of star-forming galaxies with observational iron abundance determinations to place first constraints on the [O/Fe]-sSFR relation over a wide range of sSFR. The relation shows a clear evolution towards lower [O/Fe] with decreasing sSFR and a flattening above log10(sSFR/yr) &gt; 9. These results are broadly consistent with expectations, but better constraints are needed to inform the models. We independently derive the relation from old Milky Way stars and find remarkable agreement between the two, as long as the recombination-line absolute oxygen abundance scale is used in conjunction with stellar metallicity measurements.</p

Identification of a new European rabbit IgA with a serine-rich hinge region

<div><p>In mammals, the most striking IgA system belongs to Lagomorpha. Indeed, 14 IgA subclasses have been identified in European rabbits, 11 of which are expressed. In contrast, most other mammals have only one IgA, or in the case of hominoids, two IgA subclasses. Characteristic features of the mammalian IgA subclasses are the length and amino acid sequence of their hinge regions, which are often rich in Pro, Ser and Thr residues and may also carry Cys residues. Here, we describe a new IgA that was expressed in New Zealand White domestic rabbits of <i>IGHV</i>a1 allotype. This IgA has an extended hinge region containing an intriguing stretch of nine consecutive Ser residues and no Pro or Thr residues, a motif exclusive to this new rabbit IgA. Considering the amino acid properties, this hinge motif may present some advantage over the common IgA hinge by affording novel functional capabilities. We also sequenced for the first time the IgA14 CH2 and CH3 domains and showed that IgA14 and IgA3 are expressed.</p></div

A framework for teaching computational thinking in primary schools : a Namibian case study

Several professional development programs have been designed to train in-service teachers on a computational thinking (CT) curriculum, but few researchers have examined how these affect primary school teachers' self-efficacy and knowledge of CT in emerging economies. This study's objective was to create a framework for the professional development of primary school in-service teachers for the teaching of CT (referred to as professional development for primary computational thinking - PD4PCT) to be integrated into teachers' professional development programs. An initial framework was refined after implementing it at a Namibian school with a group of 14 teachers from five different disciplines (social studies, English, natural science, mathematics, and Afrikaans). Literature reviews, pre- and post-intervention questionnaires, semi-structured interviews, and self-reporting diaries were used to collect data. The framework was evaluated by experts via an online questionnaire. The findings show that teachers who participated in the professional development program improved their perceived CT knowledge, beliefs, and confidence to teach CT.https://digitalcommons.kennesaw.edu/ajisam2024InformaticsNon

The Fundamental Plane of star formation in galaxies revealed by the EAGLE hydrodynamical simulations

We investigate correlations between different physical properties of star-forming galaxies in the ‘Evolution and Assembly of GaLaxies and their Environments’ (EAGLE) cosmological hydrodynamical simulation suite over the redshift range 0 ≤ z ≤ 4.5. A principal component analysis reveals that neutral gas fraction (fgas,neutral), stellar mass (Mstellar) and star formation rate (SFR) account for most of the variance seen in the population, with galaxies tracing a two-dimensional, nearly flat, surface in the three-dimensional space of fgas, neutral–Mstellar–SFR with little scatter. The location of this plane varies little with redshift, whereas galaxies themselves move along the plane as their fgas, neutral and SFR drop with redshift. The positions of galaxies along the plane are highly correlated with gas metallicity. The metallicity can therefore be robustly predicted from fgas, neutral, or from the Mstellar and SFR. We argue that the appearance of this ‘Fundamental Plane of star formation’ is a consequence of self-regulation, with the plane's curvature set by the dependence of the SFR on gas density and metallicity. We analyse a large compilation of observations spanning the redshift range 0 ≲ z ≲ 3, and find that such a plane is also present in the data. The properties of the observed Fundamental Plane of star formation are in good agreement with EAGLE's predictions

Building capacity and developing human capital: an exploration of curriculum development in ICT programmes at South African universities

There is a growing consensus on the potential for information and communications technologies (ICTs) to support socio-economic development in sub-Saharan Africa (SSA). Universities as providers of higher education are critical to developing SSA countries by, amongst others, empowering the region to develop appropriate ICT solutions for local challenges. The purpose of this paper is to describe and discuss how contextual realities influence the development of ICT programme curricula at public universities in South Africa, a developing country in SSA, in order to meet the demand for ICT skills. After a brief discussion of the factors that influence the content and delivery in education systems an overview of the South African public higher education context is provided. Against this background the content and delivery of ICT programme offerings and the rationale behind the programmes at four South African public universities are presented in case study format and concludes with a discussion of the case studies. The paper may be of value to academic departments as examples of how other departments are responding and adjusting their offerings, to government departments and policy makers by engendering a better understanding of the impact of policy on programme development and to industry by illustrating the diverse stakeholders in higher education and academia’s responsiveness to these diverse requirements