Bistable Helmholtz dark spatial optical solitons in materials with self-defocusing saturable nonlinearity

We present, to the best of our knowledge, the first exact dark spatial solitons of a nonlinear Helmholtz equation with a self-defocusing saturable refractive-index model. These solutions capture oblique (arbitrary-angle) propagation in both the forward and backward directions, and they can also exhibit a bistability characteristic. A detailed derivation is presented, obtained by combining coordinate transformations and direct-integration methods, and the corresponding solutions of paraxial theory are recovered asymptotically as a subset. Simulations examine the robustness of the new Helmholtz solitons, with stationary states emerging from a range of perturbed input beams

The Givenness of the Human Learning Experience and Its Incompatibility with Information Analytics

The rise of learning analytics, the application of complex metrics developed to exploit the proliferation of ‘Big Data’ in educational work, raises important moral questions about the nature of what is measurable in education. Teachers, schools and nations are increasingly held to account based on metrics, exacerbating the tendency for fine-grained measurement of learning experiences. In this article, the origins of learning analytics ontology are explored, drawing upon core ideas in the philosophy of computing, such as the general definition of information and the information-theoretic account of knowledge. Drawing upon a reading of Descartes Meditatio II, which extends the phenomenology of Jean-Luc Marion into a pedagogy of intentionality, the article identifies a fundamental incompatibility between the subjective experience of learning and the information-theoretic account of knowledge. Human subjects experience and value their own information incommensurably with the ways in which computers measure and quantify information. The consequences of this finding for the design of online learning environments, and the necessary limitations of learning analytics and measurement are explored

Building a Terrorist House on Sand: A critical incident analysis of interprofessionality and the Prevent duty in schools in England.

In 2015, a duty came into effect requiring all public bodies, including schools, to engage with the UK government’s Prevent counter-terrorism strategy. This paper presents two case studies from mid-size English cities, exploring the moral prototypes and institutional identities of professional mediators who made schools aware of their duties under Prevent. Mediators in each case included serving and former police, teachers and policy advisers, the majority of whom are now private consultants or operating small 3rd sector agencies. Drawing from in-depth interviews with 14 professionals, the paper details the ways in which participants constructed their relationship to normative, deliberative and legal obligations. The paper focuses on the recurrence of a high profile critical media incident in which a young child was allegedly subject to a referral for writing about living in a ‘terrorist’ (rather than ‘terraced’) house. Reaction to this incident was archetypal of the fear of media moral panic in reconstituting mediators’ identities as Prevent professionals, illustrating how the enframing of events shifts professional moral codes, policy interpretation and implementation

Real-Time Imaging Reveals the Dynamics of Leukocyte Behaviour during Experimental Cerebral Malaria Pathogenesis

During experimental cerebral malaria (ECM) mice develop a lethal neuropathological syndrome associated with microcirculatory dysfunction and intravascular leukocyte sequestration. The precise spatio-temporal context in which the intravascular immune response unfolds is incompletely understood. We developed a 2-photon intravital microscopy (2P-IVM)-based brain-imaging model to monitor the real-time behaviour of leukocytes directly within the brain vasculature during ECM. Ly6Chi monocytes, but not neutrophils, started to accumulate in the blood vessels of Plasmodium berghei ANKA (PbA)-infected MacGreen mice, in which myeloid cells express GFP, one to two days prior to the onset of the neurological signs (NS). A decrease in the rolling speed of monocytes, a measure of endothelial cell activation, was associated with progressive worsening of clinical symptoms. Adoptive transfer experiments with defined immune cell subsets in recombinase activating gene (RAG)-1-deficient mice showed that these changes were mediated by Plasmodium-specific CD8+ T lymphocytes. A critical number of CD8+ T effectors was required to induce disease and monocyte adherence to the vasculature. Depletion of monocytes at the onset of disease symptoms resulted in decreased lymphocyte accumulation, suggesting reciprocal effects of monocytes and T cells on their recruitment within the brain. Together, our studies define the real-time kinetics of leukocyte behaviour in the central nervous system during ECM, and reveal a significant role for Plasmodium-specific CD8+ T lymphocytes in regulating vascular pathology in this disease. © 2014 Pai et al

CD4+ Natural Regulatory T Cells Prevent Experimental Cerebral Malaria via CTLA-4 When Expanded In Vivo

Studies in malaria patients indicate that higher frequencies of peripheral blood CD4+ Foxp3+ CD25+ regulatory T (Treg) cells correlate with increased blood parasitemia. This observation implies that Treg cells impair pathogen clearance and thus may be detrimental to the host during infection. In C57BL/6 mice infected with Plasmodium berghei ANKA, depletion of Foxp3+ cells did not improve parasite control or disease outcome. In contrast, elevating frequencies of natural Treg cells in vivo using IL-2/anti-IL-2 complexes resulted in complete protection against severe disease. This protection was entirely dependent upon Foxp3+ cells and resulted in lower parasite biomass, impaired antigen-specific CD4+ T and CD8+ T cell responses that would normally promote parasite tissue sequestration in this model, and reduced recruitment of conventional T cells to the brain. Furthermore, Foxp3+ cell-mediated protection was dependent upon CTLA-4 but not IL-10. These data show that T cell-mediated parasite tissue sequestration can be reduced by regulatory T cells in a mouse model of malaria, thereby limiting malaria-induced immune pathology

CD8+ T cells from a novel T cell receptor transgenic mouse induce liver-stage immunity that can be boosted by blood-stage infection in rodent malaria

To follow the fate of CD8+ T cells responsive to Plasmodium berghei ANKA (PbA) infection, we generated an MHC I-restricted TCR transgenic mouse line against this pathogen. T cells from this line, termed PbT-I T cells, were able to respond to blood-stage infection by PbA and two other rodent malaria species, P. yoelii XNL and P. chabaudi AS. These PbT-I T cells were also able to respond to sporozoites and to protect mice from liver-stage infection. Examination of the requirements for priming after intravenous administration of irradiated sporozoites, an effective vaccination approach, showed that the spleen rather than the liver was the main site of priming and that responses depended on CD8α+ dendritic cells. Importantly, sequential exposure to irradiated sporozoites followed two days later by blood-stage infection led to augmented PbT-I T cell expansion. These findings indicate that PbT-I T cells are a highly versatile tool for studying multiple stages and species of rodent malaria and suggest that cross-stage reactive CD8+ T cells may be utilized in liver-stage vaccine design to enable boosting by blood-stage infections

A multi-criteria sustainability assessment framework: development and application in comparing two food waste management options using a UK region as a case study

This is a post-peer-review, pre-copyedit version of an article published in Environmental Science and Pollution Research. The final authenticated version is available online at: https://doi.org/10.1007/s11356-018-2479-

Beginning teacher agency in the enactment of fundamental British values: A multi-method case study.

There has been significant discussion and debate about the meaning and implementation of the requirement for schools to promote fundamental British values. While much of the research in this area focuses on surveying teachers’ attitudes, this paper set out to understand the processes of professional enactment through which beginning teachers interpret the policy agenda across sites and contexts in initial teacher education. A multi-method case study was undertaken at a large provider of initial teacher education in the North of England, following beginning teachers on project placement in primary schools. Theorising awareness and agency as axes of professional formation, the paper identifies three key thematic foci: community partnership, the treatment of inclusiveness and diversity and the professional understanding, interpretation and performance of value language. Context shapes enactment of each theme, with reflective space for criticality required if beginning teachers are to develop professional agency with regard to their role as values educators. This is a feature of the culture of placement schools, and while university-based teaching can ameliorate the effects of unreflective compliance, it cannot provide a replacement for professional acculturation. The paper explores the implications of reflection on enactment for the professional acculturation of beginning teachers, making recommendations for teacher education