1,937 research outputs found

    Seeds of Doubt: North American farmers' experiences of GM crops

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    The picture the biotechnology industry has painted of GM crops in North America is one of unqualified success, after six years of commercial growing. The objective of this report was to assess whether this image is accurate and if not what problems have occurred. We present interviews with North American farmers about their experiences of GM soya, maize and oilseed rape, and review of some of the independent research. The evidence we have gathered demonstrates that GM food crops are far from a success story. In complete contrast to the impression given by the biotechnology industry, it is clear that they have not realised most of the claimed benefits and have been a practical and economic disaster. Widespread GM contamination has severely disrupted GM-free production including organic farming, destroyed trade and undermined the competitiveness of North American agriculture overall. GM crops have also increased the reliance of farmers on herbicides and led to many legal problems. Six years after the first commercial growing of GM crops, the use of genetic engineering in global agriculture is still limited. Only four countries including the US and Canada grow 99 per cent of the GM crops grown worldwide, and just four crops account for 99 per cent of the global area planted to GM crops. In the UK, we have a choice over whether to remain GM-free. Our findings show that GM crops would obstruct the government from meeting its policy objective that farming should become more competitive and meet consumer requirements. It would also prevent it from honouring its public commitment to ensure that the expansion of organic farming is not undermined by the introduction of GM crops. The Soil Association believes this report will contribute towards a more balanced and realistic debate on the likely impacts of GM crops on farming in the UK and assist an informed decision on the commercialisation of GM crops

    Evaluating e-commerce trust using fuzzy logic [article]

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    Trust is widely recognized as an essential factor for the continual development of business to customer electronic commerce (B2C EC). Many trust models have been developed, however, most are subjective and do not take into account the vagueness and ambiguity of EC trust and the customers’ intuitions and experience when conducting online transactions. In this article, we develop a fuzzy trust model using fuzzy reasoning to evaluate EC trust. This trust model is based on the information customers expect to find on an EC Website and is shown to increase customers trust towards online merchants. We argue that fuzzy logic is suitable for trust evaluation as it takes into account the uncertainties within e-commerce data and like human relationships; it is often expressed by linguistics terms rather then numerical values. The evaluation of the proposed model will be illustrated using two case studies and a comparison with two evaluation models was conducted to emphasise the importance of usin fuzzy logic

    Is the Coulomb sum rule violated in nuclei?

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    Guided by the experimental confirmation of the validity of the Effective Momentum Approximation (EMA) in quasi-elastic scattering off nuclei, we have re-examined the extraction of the longitudinal and transverse response functions in medium-weight and heavy nuclei. In the EMA we have performed a Rosenbluth separation of the available world data on 40^{40}Ca, 48^{48}Ca, 56^{56}Fe, 197^{197}Au, 208^{208}Pb and 238^{238}U. We find that the longitudinal response function for these nuclei is "quenched" and that the Coulomb sum is not saturated, at odds with claims in the literature.Comment: 10 pages, 6 figure

    Response Function of Asymmetric Nuclear Matter

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    The charge longitudinal response function is examined in the framework of the random-phase approximation in an isospin-asymmetric nuclear matter where proton and neutron densities are different. This asymmetry changes the response through both the particle-hole interaction and the free particle-hole polarization propagator. We discuss these two effects on the response function on the basis of our numerical results in detail.Comment: 8 pages, PlainTeX file, 4 PostScript figures, uuencode

    Adaptive estimation of the density matrix in quantum homodyne tomography with noisy data

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    In the framework of noisy quantum homodyne tomography with efficiency parameter 1/2<η≀11/2 < \eta \leq 1, we propose a novel estimator of a quantum state whose density matrix elements ρm,n\rho_{m,n} decrease like Ce−B(m+n)r/2Ce^{-B(m+n)^{r/ 2}}, for fixed C≄1C\geq 1, B>0B>0 and 0<r≀20<r\leq 2. On the contrary to previous works, we focus on the case where rr, CC and BB are unknown. The procedure estimates the matrix coefficients by a projection method on the pattern functions, and then by soft-thresholding the estimated coefficients. We prove that under the L2\mathbb{L}_2 -loss our procedure is adaptive rate-optimal, in the sense that it achieves the same rate of conversgence as the best possible procedure relying on the knowledge of (r,B,C)(r,B,C). Finite sample behaviour of our adaptive procedure are explored through numerical experiments
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