Meson-baryon interaction in the meson exchange picture

This is the contribution to the proceedings of the MENU 2010 conference. The recent work of Ref. [7] is summarized. Elastic piN scattering and the reaction pi^+ p --> K^+ Sigma^+ are described simultaneously in a unitary coupled-channels approach which respects analyticity. SU(3) flavor symmetry is used to relate the t- and u- channel exchanges that drive the meson-baryon interaction in the different channels. Angular distributions, polarizations, and spin-rotation parameters are compared with available experimental data. The pole structure of the amplitudes is extracted from the analytic continuation.Comment: 4 pages, contribution to the proceedings of the MENU 2010 conference, May 31- June 4, 2010, Williamsburg VA, US

What May I Hope? Why It Can Be Rational to Rely on One’s Hope

In hoping, what is important to us seems possible, which makes our life appear meaningful and motivates us to do everything within our reach to bring about the things that we hope for. I argue that it can be rational to rely on one’s hope: hope can deceive us, but it can also represent things correctly to us. I start with Philip Pettit’s view that hope is a cognitive resolve. I reject this view and suggest instead that hope is an emotion: hope is a felt evaluation for which we can define a corresponding character trait which in its turn qualifies as a virtue if it is felt whenever its correctness conditions are satisfied. For religious hope in particular it follows from my analysis that, if I believe, I may hope

Potential and limitations of plant virus epidemiology: lessons from the Potato virus Y pathosystem

Abstract Plant virus epidemiology provides powerful tools to investigate key factors that contribute to virus epidemics in agricultural crops. When successful, epidemiological approaches help to guide decisions regarding plant protection strategies. A recent example is epidemiological research on Potato virus Y (PVY) in Finnish seed potato production; this study led to the dentification of the main PVY vector species and helped to determine the timing of virus transmission. However, pathosystems rarely allow research to produce such clear-cut results. In fact, the notorious complexity of plant virus pathosystems, with multiple interactions between virus, vector, plant and environment, makes them often impenetrable even for advanced epidemiological models. This dynamic complexity questions the universal validity of employing epidemiological models that attempt to single out key factors in plant virus epidemics. Therefore, a complementary approach is needed that acknowledges the partly indeterministic nature of complex and evolving pathosystems. Such an approach is the use of diversity, imploying functionally complementary elements that can jointly buffer against environmental changes. I argue that for a wider range of plant production problems, the strategy of combining mechanistic and diversity-based approaches will provide potent and sustainable solutions. In addition, to translate insights from plant virus epidemiology into practice, improvements need to be made in knowledge transfer, both within the scientific community and between researchers and practitioners. Finally, moving towards more appropriate virus control strategies is only possible if economic interests of all stakeholders are in line with changing current practices

Three-body Unitarity in the Finite Volume

The physical interpretation of lattice QCD simulations, performed in a small volume, requires an extrapolation to the infinite volume. A method is proposed to perform such an extrapolation for three interacting particles at energies above threshold. For this, a recently formulated relativistic $3\to 3$ amplitude based on the isobar formulation is adapted to the finite volume. The guiding principle is two- and three-body unitarity that imposes the imaginary parts of the amplitude in the infinite volume. In turn, these imaginary parts dictate the leading power-law finite-volume effects. It is demonstrated that finite-volume poles arising from the singular interaction, from the external two-body sub-amplitudes, and from the disconnected topology cancel exactly leaving only the genuine three-body eigenvalues. The corresponding quantization condition is derived for the case of three identical scalar-isoscalar particles and its numerical implementation is demonstrated.Comment: 9 pages, 3 figure

Sterile Neutrino Shortcuts in Asymmetrically Warped Extra Dimensions

Light sterile neutrinos are a popular extension of the Standard Model and are being discussed as a possible explanation for various neutrino oscillation anomalies, including the LSND, MiniBooNE, Reactor and Gallium anomalies. In order to avoid inconsistencies with constraints derived from disappearance experiments and cosmology, altered dispersion relations - which may originate from extra dimensions - have been proposed as a possible solution, dubbed as "neutrino shortcuts in the extra dimension". In this paper we develop a neutrino mass model with an asymmetrically warped extra dimension and two additional gauge singlet neutrinos, one being responsible for neutrino mass generation, while the other one is allowed to propagate in the extra dimension, giving rise to the desired change of the dispersion relation on the brane. By compactifying the extra-dimensional theory on an $S^1/\mathbb{Z}_2$ orbifold, deriving the shape of the Kaluza-Klein tower and identifying the effective sterile neutrino dispersion relation on the brane, we can demonstrate that the earlier, phenomenological models are recovered as the 4-dimensional effective field theory limit of the model discussed here.Comment: 15 page

There is nothing like an oat

The items reports on first year trials in of the “Quoats” project. It’s well known that oats are generally a good fit in organic rotations and the “Quoats” project – Harnessing new technologies for sustainable oat production and utilisation – aims to make them even better. This five year (2009 – 2014) research project, led by IBERS, Aberystwyth University, brings together a wide range of organisations in the supply chain, from breeders to end-users, to improve the quality and performance of oats. As part of the project, ORC is carrying out field trials to assess the suitability of new oat lines for organic management systems, with particular emphasis on nutrient use efficiency. Eight varieties are being trialled at Wakelyns Agroforestry, Suffolk, including some naked oats, i.e. hull-less oats. The paper reports some first results

Legume Pick ‘n’ Mix

In Spring 2009, ORC set up a legume trial on an organic farm, Barrington Park in Gloucestershire, as part of a large research project called Legume LINK. One of its aims is to compare the performance of several legume and grass species for use in fertility building leys. ORC researchers Thomas Döring and Oliver Crowley report that the trial shows the advantage of mixing species grows over time

Regression calibration for Cox regression under heteroscedastic measurement error - Determining risk factors of cardiovascular diseases from error-prone nutritional replication data

For instance nutritional data are often subject to severe measurement error, and an adequate adjustment of the estimators is indispensable to avoid deceptive conclusions. This paper discusses and extends the method of regression calibration to correct for measurement error in Cox regression. Special attention is paid to the modelling of quadratic predictors, the role of heteroscedastic measurement error, and the efficient use of replicated measurements of the surrogates. The method is used to analyze data from the German part of the MONICA cohort study on cardiovascular diseases. The results corroborate the importance of taking into account measurement error carefully

Saving fuel with non-inversion tillage

The mouldboard plough is the traditional and proven method of preparing a seedbed for drilling and controlling arable weeds. However there is a downside; trials have shown deterioration in structural stability, losses of soil organic matter, poor moisture retention and infiltration rates (Riley et al 2008). Farmers have long been aware of these adverse impacts of mouldboard ploughing, but concerns over the greenhouse gas emissions associated with tractor usage have prompted a fresh look at cultivations. ORC researchers, Oliver Crowley, Jemima Showering and Thomas F. Döring consider the case for non-inversion tillage