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 Effects of Written Prompts on Homework Compliance and Outcome in a Cognitive Behavioural Treatment for Depression and Research Portfolio

Objectives: To test whether between-session written prompts would increase quantity and quality of compliance with homework assignments and improve the overall outcome effects in a cognitive behavioural treatment (CBT) for depression, independent of the effects of therapeutic empathy and motivation. Design: A single-subject-series repeated-measures design was used as this was considered to be the most effective way to investigate the hypotheses with the small n involved. The intervention was introduced using a multiple baseline across participants. Methods: Participants were seven outpatients referred to a community clinical psychology servtce. Assessment with The Structured Clinical Interview (SCID-IV) indicated that all were suffering from recurrent uni-polar depression. They were treated using CBT. The independent variable was the prompting letter. The dependent variables were therapist ratings of homework compliance and outcome (Hamilton Depressive Rating Scales) and patient self-ratings of motivation, therapeutic empathy, and outcome (including Beck Depression Inventory-II). Results: Prompting appeared to improve the quantity of compliance but not the quality. There was no clear indication that prompts were effective in improving outcome. Increases in quantity of compliance seemed to have a close association with increases in motivation. No such association was found with therapeutic empathy. Conclusions: Written prompts are an effective way of improving quantity of compliance with homework. This simple cost-effective method could improve the efficacy of various psychological and non-psychological treatments where non-compliance is an issue

Abinitioparameterisation of the 14 band k·p Hamiltonian: Zincblende study

Despite continued and rapid progress in high performance computing, atomistic level device modelling is still largely out of reach, necessitating the use of quantum mechanical continuum methods, including kcenterdotp perturbation theory. The effective use of such methods requires reliable parameterisation, often obtained from experiment and ab initio calculations. A major limitation of this, the systematic tendency of ab initio density functional theory to underestimate semiconducting material energy band gaps and related properties, can be greatly improved upon by the inclusion of exact exchange, calculated within the Hartree-Fock formalism. We demonstrate that the 14 band kcenterdotp Hamiltonian can be effectively parameterised using this method, at greatly reduced cost in comparison to G

Carbon Monoxide-Dependent Chemolithotrophic Growth of Clostridium thermoautotrophicum

The acetogen Clostridium thermoautotrophicum was cultivated under CO-dependent chemolithotrophic conditions. CO-dependent growth profiles and energetics indicated that supplemental CO2 was fundamental to efficient growth at the expense of CO. Overall product stoichiometry approximated 6.5CO --\u3e CH3CO2H + 3.5CO2 + 0.6 cell C + 0.5 unrecovered C. Initial CO/CO2 ratios of 2 to 4 yielded optimal doubling times and cell yields. Maximal YCO values approximated 2.5 g of cell dry weight per mol of CO consumed; Y H2 , was considerably lower than Y CO Cross-transfer growth experiments and protein profiles indicated differential expression of genes between CO and methanol cultures

Carbon Monoxide-Dependent Chemolithotrophic Growth of Clostridium thermoautotrophicum

The acetogen Clostridium thermoautotrophicum was cultivated under CO-dependent chemolithotrophic conditions. CO-dependent growth profiles and energetics indicated that supplemental CO2 was fundamental to efficient growth at the expense of CO. Overall product stoichiometry approximated 6.5CO --\u3e CH3CO2H + 3.5CO2 + 0.6 cell C + 0.5 unrecovered C. Initial CO/CO2 ratios of 2 to 4 yielded optimal doubling times and cell yields. Maximal YCO values approximated 2.5 g of cell dry weight per mol of CO consumed; Y H2 , was considerably lower than Y CO Cross-transfer growth experiments and protein profiles indicated differential expression of genes between CO and methanol cultures

A central role for hepatic conventional dendritic cells in supporting Th2 responses during helminth infection

Dendritic cells (DCs) are the key initiators of T-helper (Th) 2 immune responses against the parasitic helminth Schistosoma mansoni. Although the liver is one of the main sites of antigen deposition during infection with this parasite, it is not yet clear how distinct DC subtypes in this tissue respond to S. mansoni antigens in vivo, or how the liver microenvironment might influence DC function during establishment of the Th2 response. In this study, we show that hepatic DC subsets undergo distinct activation processes in vivo following murine infection with S. mansoni. Conventional DCs (cDCs) from schistosome-infected mice upregulated expression of the costimulatory molecule CD40 and were capable of priming naive CD4+ T cells, whereas plasmacytoid DCs (pDCs) upregulated expression of MHC class II, CD86 and CD40 but were unable to support the expansion of either naive or effector/memory CD4+ T cells. Importantly, in vivo depletion of pDCs revealed that this subset was dispensable for either maintenance or regulation of the hepatic Th2 effector response during acute S. mansoni infection. Our data provides strong evidence that S. mansoni infection favors the establishment of an immunogenic, rather than tolerogenic, liver microenvironment that conditions cDCs to initiate and maintain Th2 immunity in the context of ongoing antigen exposure

Type I interferon is required for T helper (Th) 2 induction by dendritic cells

Type 2 inflammation is a defining feature of infection with parasitic worms (helminths), as well as being responsible for widespread suffering in allergies. However, the precise mechanisms involved in T helper (Th) 2 polarization by dendritic cells (DCs) are currently unclear. We have identified a previously unrecognized role for type I IFN (IFN-I) in enabling this process. An IFN-I signature was evident in DCs responding to the helminth Schistosoma mansoni or the allergen house dust mite (HDM). Further, IFN-I signaling was required for optimal DC phenotypic activation in response to helminth antigen (Ag), and efficient migration to, and localization with, T cells in the draining lymph node (dLN). Importantly, DCs generated from Ifnar1-/- mice were incapable of initiating Th2 responses in vivo. These data demonstrate for the first time that the influence of IFN-I is not limited to antiviral or bacterial settings but also has a central role to play in DC initiation of Th2 responses

RNA:DNA hybrids are a novel molecular pattern sensed by TLR9.

The sensing of nucleic acids by receptors of the innate immune system is a key component of antimicrobial immunity. RNA:DNA hybrids, as essential intracellular replication intermediates generated during infection, could therefore represent a class of previously uncharacterised pathogen-associated molecular patterns sensed by pattern recognition receptors. Here we establish that RNA:DNA hybrids containing viral-derived sequences efficiently induce pro-inflammatory cytokine and antiviral type I interferon production in dendritic cells. We demonstrate that MyD88-dependent signalling is essential for this cytokine response and identify TLR9 as a specific sensor of RNA:DNA hybrids. Hybrids therefore represent a novel molecular pattern sensed by the innate immune system and so could play an important role in host response to viruses and the pathogenesis of autoimmune disease

A theory of motivation and ontological enhancement: the role of disability policy in student empowerment and institutional change

As debate continues around the nature and values of education, it is important to ask the question of what factors motivate a student to engage with the ends of an educational institution. In this paper, a broad, holistic view of learner motivation, derived from Aristotelian ethics, is used to provide a model to drive institutional change. Focussing on the approach of one Higher Education institution to the particular accommodations required for students with disabilities, the paper identifies three factors which motivate students, a failure to engage with the aims and ends of the educational project, a failure to see that a particular learning aim is worth attaining, and a simple lack of will‐power to attain it. To each of these failures a social cause is identified, and a change in both the institutional culture and the individual learner's approach to their education is suggested