Picturing Pedagogy: Images, Teaching, and Development

Images are powerful. They shape how we see and understand the world and, in the process, challenge (or reinforce) our assumptions and perspectives. The images we use in the classroom are no exception, whether used passively as visual aids or as a “medium through which active learning is energized.”1 In this article we embrace the “pictorial turn” in university teaching and reflect on the use of images when teaching “development.”2 Development is an area that typically attracts students with an internationalist orientation and who seek to make a positive change in the world. Yet the concept of development is fraught in historical and political economic terms. Its complexity is reflected in academic debates about developmental imageries and imaginaries and, in particular, in representing global poverty. We argue that, by using images carefully and reflectively, we can help students think critically about the development project’s history and imperial dimensions whilst nurturing their desire to either struggle against global injustices or improve life and livelihood in particular places. We write from the standpoint of teachers in postgraduate education in both law and cognate disciplines. Our aim is to equip students with the kinds of contextual understandings and critical intellectual tools which help them to become engaged agents of change

The radiation field on product cones

We consider the wave equation on a product cone and find a joint asymptotic expansion for forward solutions near null and future infinities. The rates of decay seen in the expansion are the resonances of a hyperbolic cone on the "northern cap" of the compactification and were computed by the authors in a previous paper. The expansion treats an asymptotic regime not considered in the influential work of Cheeger and Taylor. The main result follows the blueprint laid out in the asymptotically Minkowski setting; the key new element consists of propagation estimates near the conic singularities. The proof of the propagation estimates builds on the work of Melrose--Vasy--Wunsch in the spacetime and on Gannot--Wunsch in the semiclassical regime.Comment: 38 pages, 3 figures. The main result builds on previous work of the first author with Vasy and Wunsch (arXiv:1212.5141 and arXiv:1602.04795), the propagation estimates in the bulk build on the work of Melrose--Vasy--Wunsch (arXiv:math/0612750), and the semiclassical propagation estimates build on work of Gannot--Wunsch (arXiv:1806.01813

Price's law on Minkowski space in the presence of an inverse square potential

We consider the pointwise decay of solutions to wave-type equations in two model singular settings. Our main result is a form of Price's law for solutions of the massless Dirac-Coulomb system in (3+1)-dimensions. Using identical techniques, we prove a similar theorem for the wave equation on Minkowski space with an inverse square potential. One novel feature of these singular models is that solutions exhibit two different leading decay rates at timelike infinity in two regimes, distinguished by whether the spatial momentum along a curve which approaches timelike infinity is zero or non-zero. An important feature of our analysis is that it yields a precise description of solutions at the interface of these two regions which comprise the whole of timelike infinity.Comment: 14 pages, 2 figures; version 2: significant revisions, emphasized Dirac-Coulomb application and clarified expositio

Copper-free click chemistry for the in situ crosslinking of photodegradable star polymers

Bifunctional, fluorinated cyclooctynes were used for the in situ click crosslinking of azide-terminated photodegradable star polymers, yielding photodegradable polymeric model networks with well-defined structures and tunable gelation times

Crosslinking Studies of Protein-Protein Interactions in Nonribosomal Peptide Biosynthesis

SummarySelective protein-protein interactions between nonribosomal peptide synthetase (NRPS) proteins, governed by communication-mediating (COM) domains, are responsible for proper translocation of biosynthetic intermediates to produce the natural product. In this study, we developed a crosslinking assay, utilizing bioorthogonal probes compatible with carrier protein modification, for probing the protein interactions between COM domains of NRPS enzymes. Employing the Huisgen 1,3-dipolar cycloaddition of azides and alkynes, we examined crosslinking of cognate NRPS modules within the tyrocidine pathway and demonstrated the sensitivity of our panel of crosslinking probes toward the selective protein interactions of compatible COM domains. These studies indicate that copper-free crosslinking substrates uniquely offer a diagnostic probe for protein-protein interactions. Likewise, these crosslinking probes serve as ideal chemical tools for structural studies between NRPS modules where functional assays are lacking

Live-Cell Imaging of Cellular Proteins by a Strain-Promoted Azide–Alkyne Cycloaddition

Live and let dye: Three coumarin-cyclooctyne conjugates have been used to label proteins tagged with azidohomoalanine in Rat-1 fibroblasts. All three fluorophores labeled intracellular proteins with fluorescence enhancements ranging from eight- to 20-fold. These conjugates are powerful tools for visualizing biomolecule dynamics in living cells

Rare deleterious mutations of the gene EFR3A in autism spectrum disorders

Background: Whole-exome sequencing studies in autism spectrum disorder (ASD) have identified de novo mutations in novel candidate genes, including the synaptic gene Eighty-five Requiring 3A (EFR3A). EFR3A is a critical component of a protein complex required for the synthesis of the phosphoinositide PtdIns4P, which has a variety of functions at the neural synapse. We hypothesized that deleterious mutations in EFR3A would be significantly associated with ASD. Methods: We conducted a large case/control association study by deep resequencing and analysis of whole-exome data for coding and splice site variants in EFR3A. We determined the potential impact of these variants on protein structure and function by a variety of conservation measures and analysis of the Saccharomyces cerevisiae Efr3 crystal structure. We also analyzed the expression pattern of EFR3A in human brain tissue. Results: Rare nonsynonymous mutations in EFR3A were more common among cases (16 / 2,196 = 0.73%) than matched controls (12 / 3,389 = 0.35%) and were statistically more common at conserved nucleotides based on an experiment-wide significance threshold (P = 0.0077, permutation test). Crystal structure analysis revealed that mutations likely to be deleterious were also statistically more common in cases than controls (P = 0.017, Fisher exact test). Furthermore, EFR3A is expressed in cortical neurons, including pyramidal neurons, during human fetal brain development in a pattern consistent with ASD-related genes, and it is strongly co-expressed (P < 2.2 × 10−16, Wilcoxon test) with a module of genes significantly associated with ASD. Conclusions: Rare deleterious mutations in EFR3A were found to be associated with ASD using an experiment-wide significance threshold. Synaptic phosphoinositide metabolism has been strongly implicated in syndromic forms of ASD. These data for EFR3A strengthen the evidence for the involvement of this pathway in idiopathic autism

The Struggle for Legitimacy: South Africa’s Divided Labour Movement and International Labour Organisations, 1919–2019

Who could be considered a legitimate representative of South Africa’s working class, and even who constituted this class, was bitterly contested during the twentieth century. This chapter examines the struggles for international recognition by the rival constituents of South Africa’s labour movement, which was sharply divided along racial and ideological lines. Initially, the International Labour Organization and other similar bodies formed links with the white-dominated labour movement, which regarded itself as the legitimate representative of all workers in South Africa. This position was successfully contested by emerging black African trade unions who themselves, in the face of fierce repression, competed for financial support made available by various sections of the international labour movement