Positronium scattering by Ne, Ar, Kr and Xe in the frozen target approximation

A full-electron coupled-state treatment of positronium (Ps)- inert gas scattering is developed within the context of the frozen target approximation. Calculations are performed for Ps(Is) scattering by Ne and Ar in the impact energy range 0-40 eV using coupled pseudostate expansions consisting of nine and 22 Ps states. The purpose of the pseudostates is primarily to represent ionization of the Ps which is found to be a major process at the higher energies. First Born estimates of target excitation are used to complement the frozen target results. The available experimental data are discussed in detail. It is pointed out that the very low energy measurements (less than or equal to2 eV) correspond to the momentum transfer cross section sigma(mom) and not to the elastic cross section sigma(el). Calculation shows that sigma(mom), and sigma(el) diverge very rapidly with increasing energy and consequently comparisons of the low-energy data with ITel can be very misleading. Agreement between the calculations and the low-energy measurements of anion as well;as higher energy (greater than or equal to15 eV) beam measurements of the total cross section, is less than satisfactory. Results for Ps(1s) scattering by Kr and Xe in the static-exchange approximation are also presented.

Addressing diversity and inclusion in the early years in conflict-affected societies: A case study of the Media Initiative for Children – Northern Ireland

This article reports on the development and systematic evaluation of an innovative early years programme aimed at encouraging young children to respect differences within a deeply-divided society that is emerging out of a prolonged period of violent conflict. The programme, the Media Initiative for Children – Northern Ireland, has been the product of a partnership between an US-based organisation (the Peace Initiatives Institute) and NIPPA – The Early Years Organisation and has been supported by academic research and the efforts of a range of voluntary and statutory organisations. It has attempted to encourage young children to value diversity and be more inclusive of those who are different to themselves through the use of short cartoons designed for and broadcast on television as well as specially-prepared curricular materials for use in pre-school settings. To date the programme has been delivered through 200 settings to approximately 3,500 pre-school children across Northern Ireland. This article describes how the programme was developed and implemented as well as the rigorous approach taken to evaluating its effects on young children’s attitudes and awareness. Key lessons from this are identified and discussed in relation to future work in this area.

Fasciola hepatica cathepsin L-like proteases: biology, function and potential in the development of first generation liver fluke vaccines.

Fasciola hepatica secretes cathepsin L proteases that facilitate the penetration of the parasite through the tissues of its host, and also participate in functions such as feeding and immune evasion. The major proteases, cathepsin L1 (FheCL1) and cathepsin L2 (FheCL2) are members of a lineage that gave rise to the human cathepsin Ls, Ks and Ss, but while they exhibit similarities in their substrate specificities to these enzymes they differ in having a wider pH range for activity and an enhanced stability at neutral pH. There are presently 13 Fasciola cathepsin L cDNAs deposited in the public databases representing a gene family of at least seven distinct members, although the temporal and spatial expression of each of these members in the developmental stage of F. hepatica remains unclear. Immunolocalisation and in situ hybridisation studies, using antibody and DNA probes, respectively, show that the vast majority of cathepsin L gene expression is carried out in the epithelial cells lining the parasite gut. Within these cells the enzyme is packaged into secretory vesicles that release their contents into the gut lumen for the purpose of degrading ingested host tissue and blood. Liver flukes also express a novel multi-domain cystatin that may be involved in the regulation of cathepsin L activity. Vaccine trials in both sheep and cattle with purified native FheCL1 and FheCL2 have shown that these enzymes can induce protection, ranging from 33 to 79%, to experimental challenge with metacercariae of F. hepatica, and very potent anti-embryonation/hatch rate effects that would block parasite transmission. In this article we review the vaccine trials carried out over the past 8 years, the role of antibody and T cell responses in mediating protection and discuss the prospects of the cathepsin Ls in the development of first generation recombinant liver fluke vaccines. Author Keywords: Helminths; Trematodes; Parasites; Cathepsins; Proteases; Vaccines; Immunology; Biochemistry