African Postharvest Losses Information System – a network for the estimation of cereal weight losses

Soaring food prices during 2007/2008, and the realisation that sporadic food shortages are likely to continue long into the future, has reawakened interest in the benefits of reducing food losses. As a means of making more accurate estimates of how much food is lost, the Joint Research Centre (European Commission) proposed the development of the African Postharvest Losses Information System (APhLIS) (http://www.phlosses.net). APhLIS estimates postharvest losses (PHLs) by cereal crop, by country and by province in East and Southern Africa. The system went live in March 2009 and combines a loss calculator, a free access database of key information, and a network of local experts who contribute the latest data and verify loss estimates. The loss calculator works of loss figures contributed from the literature and by local experts but also takes account of the prevailing climate, scale of farming (small/large), damp weather at harvest, larger grain borer (in the case of maize), proportion of grain held in farm sorage or marketed, and multiple harvests. Before the introduction of APhLIS, the origin and justification of PHL estimates were not well founded. Now PHL estimates are available that are • Transparent in the way they are calculated• Based on a complete screening of available research and literature• Contributed (in part) and verified by local experts• Based on the primary national unit (i.e. province not just country level, so estimates are more relevant)• Upgradeable as more (reliable) data become available, so that there is the opportunity for increasing accuracy in loss estimation over time.• Supported by a downloadable loss calculator that can be used to make loss calculations at ageographical scale below primary national unit.In the future, APhLIS may be expanded in technical scope (crops) and geographical range (countries) and used to help prioritize and justify loss reduction strategies including those for grain storage.Keywords: Weight loss, Loss calculator, Postharvest operations, Cereal suppl

Detecting and Studying Higgs Bosons at a Photon-Photon Collider

We examine the potential for detecting and studying Higgs bosons at a photon-photon collider facility associated with a future linear collider. Our study incorporates realistic \gam\gam luminosity spectra based on the most probable available laser technology. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson; b) the heavy MSSM Higgs bosons; c) a Higgs boson with no $WW/ZZ$ couplings from a general two Higgs doublet model.Comment: 52 pages, 26 figures, revised version with new appendi

The potential for aflatoxin predictive risk modelling in sub-Saharan Africa: a review

This review presents the current state of aflatoxin risk prediction models and their potential for value actors throughout the food chain in sub-Saharan Africa, with a specific focus on improving smallholder farmer management practices. Several empirical and mechanistic models have been developed either in academic research or by private sector aggregators and processors in high-income countries including Australia, the USA, and Southern Europe, but these models have been only minimally applied in sub-Saharan Africa, where there is significant potential and increasing need due to climate variability. Predictions can be made based on historic occurrence data using either a mechanistic microbiological framework for aflatoxin accumulation or an empirical model based on statistical correlations with climate conditions and local agronomic factors. Model results can then be distributed to smallholders through private, public, or mobile extension services, used by policymakers for strategy or policy, or utilised by private sector institutions for management decisions. Specific agricultural advice can be given during the three most critical points in the phenological cycle: preseason insight including sowing timing and crop varieties, preharvest advice about management and harvest timing, and postharvest optimal practices including storage, drying, and market information. Model development for sub-Saharan Africa is limited by a dearth of georeferenced aflatoxin occurrence data and real-time high resolution climate data; the wide diversity of farm typologies each with significant information and technology gaps; a prevalence of informal market structures and lack of economic incentives systems; and general lack of awareness around aflatoxins and best management practices to mitigate risk. Given advancements towards solving these challenges, predictive aflatoxin models can be integrated into decision support platforms to focus on optimisation of value for smallholders by minimising yield and nutritional losses, which can propagate value throughout the production and postharvest phases

A Novel Electrical Method to Measure Wire Tensions for Time Projection Chambers

We present a novel electrical technique to measure the tension of wires in multi-wire drift chambers. We create alternating electric fields by biasing adjacent wires on both sides of a test wire with a superposition of positive and negative DC voltages on an AC signal ($V_{\rm AC} \pm V_{\rm DC}$). The resulting oscillations of the wire will display a resonance at its natural frequency, and the corresponding change of the capacitance will lead to a measurable current. This scheme is scalable to multiple wires and therefore enables us to precisely measure the tension of a large number of wires in a short time. This technique can also be applied at cryogenic temperatures making it an attractive solution for future large time-projection chambers such as the DUNE detector. We present the concept, an example implementation and its performance in a real-world scenario and discuss the limitations of the sensitivity of the system in terms of voltage and wire length.Comment: 7 pages, 8 figures. Accepted by NIM

Studies for a Photon Collider at the ILC

One option at the International Linear Collider is to convert the electron beams into high energy photon beams by Compton scattering a few millimetres in front of the interaction region. Selected physics channels for this option have been analysed and technical issues have been studied. So far no showstoppers for this option have been found.Comment: V2: Minor changes, accepted by NI

Strong Coupling Constant from the Photon Structure Function

We extract the value of the strong coupling constant alpha_s from a single-parameter pointlike fit to the photon structure function F_2^gamma at large x and Q^2 and from a first five-parameter full (pointlike and hadronic) fit to the complete F_2^gamma data set taken at PETRA, TRISTAN, and LEP. In next-to-leading order and the MSbar renormalization and factorization schemes, we obtain alpha_s(m_Z)=0.1183 +/- 0.0050(exp.)^+0.0029_-0.0028(theor.) [pointlike] and alpha_s(m_Z)=0.1198 +/- 0.0028(exp.)^+0.0034_-0.0046(theor.) [pointlike and hadronic]. We demonstrate that the data taken at LEP have reduced the experimental error by about a factor of two, so that a competitive determination of alpha_s from F_2^gamma is now possible.Comment: 11 pages, 2 tables, 2 figures. Version accepted for publication by Phys. Rev. Let

Gamma(*)Gamma(*) reaction at high energies

The energy available for gamma(*)gamma(*) physics at LEP2 is opening a new window on the study of diffractive phenomena, both non-perturbative and perturbative. We discuss some of the uncertainties and problems connected with the experimental measurements and their interpretation.Comment: 6 pages, 6 figures, submitted to proceedings of the Durham Collider Workshop, 22-26 September 199