122 research outputs found
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
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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
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