Comparison of regge models of pion-nucleon scattering and related processes

A phenomenological analysis of pion nucleon scattering at high energies is presented in terms of soveral absorptive models for the πN amplitudes. In the past there have been two popular versions - the weak-cut model and the strong-cut model. In general it was difficult to choose between these- two very different approaches. However the whole absorptive approach was thrown into doubt when better information about the polarization in π p→ π(^o) n at larger ׀t׀ became available, last year. The new data in fact accords with the predictions of the p + p(^1) polo lit of Barger and Phillips, More recently measurements of the R parameter in π(^+)ρ→ π(^+)ρ have enabled the phases of the πN amplitudes to be determined, and again these agree with the Barber-Phillips (B.P) productions but contradict both types of absorption model. We assume that the B.P It = 0 amplitudes are a reliable T-representation of these amplitudes, and we fit those with a somewhat simpler parameterization. For our I(_t). = 1 amplitudes, we find that a t-channel parameterization plus crossing was much preferred to the usual direct s-channel parameterization. We find, cy correctly taking into account the real parts of the I(_t) = 0 non-flip amplitude i.e essentially, by including a p o p cut contribution in the I(_t) = 1 amplitudes, that our fits improved considerably, especially the charge-exchange polarization. We find that the fixed-pole coupling model is by far the best. In general the data is reasonably well fitted apart from the high ׀t| region of our elastic polarisation. This is traced back to our rather poor representation of the real parts of the I(_t) = 1 amplitudes. It is unlikely that a better representation of the- I(_t) = 0 amplitudes will remedy this defect. The imaginar parts of these amplitudes- are in good agreement with amplitude analysis. We conclude that the absorption prescription, with any hypothesis about the choosing mechanism of the p pole is not completely successful in explaining the I(_t)= 1 amplitudes. It works well for the imaginary parts and less so for the real parts, and we indicate, possible, reasons for this

The export potential of traditional varieties of rice from Bangladesh

This research is funded by the Overseas Development Administration's Crops Post Harvest Programme. The objective of the research is to bring together information on prevailing quality/price relationships for traditional varieties of rice in Bangladesh and for competing products on the world market in order to make a judgement about Bangladesh's ability to enter the export trade for speciality rices

Rural livelihoods, empowerment and the environment: Going beyond the farm boundary

The 15th International Symposium of the Association for farming Systems Research-Extension (AFSR-E) was held at the University of Pretoria between 29 November and 4 December 1998 with the theme of "Rural livelihoods, empowerment and the environment: Going beyond the farm boundary". The conference was sponsored by twenty organisations involved in farming systems research (a list of sponsors is attached as Appendix 1) and was attended by 560 delegates from more than seventy countries (delegate list attached as Appendix 2). The Symposium addressed five sub-themes: ecological sustainable development and farming systems; short term farmer survival versus long term sustainability; empowerment through capacity building; the institutional environment and farming systems; and methodological issues and challenges

Report on a visit to Tanzania to review ram presses for Appropriate Technology International

This visit report provides details of the main findings of a study (carried out during 13 February – 5 March 1993) of ram presses in use in Tanzania. The assignment was undertaken on contract by Tony Swetman (Oilseed Technologist) of the Natural Resources Institute (NRI) on behalf of Appropriate Technology International (ATI)

Small scale vegetable oil extraction

The processes required to manufacture human food from oilseeds and nuts vary considerably, depending on the raw materials and the scale of the operation. Large-scale producers can select equipment from a range of manufacturers, but the choice for smaller manufacturers is generally limited. Small-Scale Vegetable Oil Extraction presents the options available for processing a range of common oilseeds from domestic to village scales of operation. Details are provided on the type and source of equipment, and the requirements for financial success are examined. The publication will be of interest both to entrepreneurs and NGOs considering setting up oilseed operations

Further Improvements of the P. falciparum Humanized Mouse Model

BACKGROUND: It has been shown previously that it is possible to obtain growth of Plasmodium falciparum in human erythrocytes grafted in mice lacking adaptive immune responses by controlling, to a certain extent, innate defences with liposomes containing clodronate (clo-lip). However, the reproducibility of those models is limited, with only a proportion of animals supporting longstanding parasitemia, due to strong inflammation induced by P. falciparum. Optimisation of the model is much needed for the study of new anti-malarial drugs, drug combinations, and candidate vaccines. MATERIALS/METHODS: We investigated the possibility of improving previous models by employing the intravenous route (IV) for delivery of both human erythrocytes (huRBC) and P. falciparum, instead of the intraperitoneal route (IP), by testing various immunosuppressive drugs that might help to control innate mouse defences, and by exploring the potential benefits of using immunodeficient mice with additional genetic defects, such as those with IL-2Rγ deficiency (NSG mice). RESULTS: We demonstrate here the role of aging, of inosine and of the IL-2 receptor γ mutation in controlling P. falciparum induced inflammation. IV delivery of huRBC and P. falciparum in clo-lip treated NSG mice led to successful infection in 100% of inoculated mice, rapid rise of parasitemia to high levels (up to 40%), long-lasting parasitemia, and consistent results from mouse-to-mouse. Characteristics were closer to human infection than in previous models, with evidence of synchronisation, partial sequestration, and receptivity to various P. falciparum strains without preliminary adaptation. However, results show that a major IL-12p70 inflammatory response remains prevalent. CONCLUSION: The combination of the NSG mouse, clodronate loaded liposomes, and IV delivery of huRBC has produced a reliable and more relevant model that better meets the needs of Malaria research

Being Married

2009/04/21. Explores how the church is to embody the reality of the new world of God\u27s kingdom, illustrated through their own experience of marriage as co-submission. Pastors, Vineyard Community Church

Photocatalyzed Hydrogen Evolution Using Nickel-Bound Metallothionein Protein

The continued burning of fossil fuels is not only a cause of increasing deterioration of the environment but also a financially unsustainable source of energy. Advances in energy production must be investigated to avoid the long-term effects of this current main source of energy. One of the avenues being explored is the use of metalloenzymes to catalyze hydrogen evolution via water splitting that occurs during the reductive half of artificial photosynthesis. Metalloenzyme catalysts with a single Ni(Cys)4 active site have been previously studied, and this study explores the possibility of increasing hydrogen production by using metalloenzyme catalysts with multiple Ni(Cys)4 active sites. The protein α-metallothionein and 4 de novo designed mutants of this protein are synthesized and purified before being anaerobically bound to the metal nickel. A photosensitizer and an electron donor are added to Ni3-αMT and the 4 Ni1-αMT mutants, respectively, and the samples are dissolved in a buffer. Hydrogen gas is produced by the solutions when they are irradiated with white light. The production is quantified using gas chromatography, and the results of this study suggest that multi-metallic active sites are positively correlated with photocatalytic hydrogen evolution. The strength of Ni-Cys coordination in different clusters in the αMT sequence is also observed through comparison of the 4 mutants