15,715 research outputs found

    Mixers: A participatory approach to design prototyping

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    In this design exhibit, we describe methods we have used to design a noticeboard interface for an older community in London. Three low-fidelity methods of prototyping interaction provided shared and accessible means for us and our end users to communicate design ideas, explore qualities of the user experience, and evaluate them within situations of use. This approach facilitated the development of an appropriate, innovative and feasible solution for a unique context

    Assessing the ecological soundness of organic and conventional agriculture by means of life cycle assessment (LCA) - a case study of leek production

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    Purpose – Sustainable agriculture implies the ability of agro-ecosystems to remain productive in the long-term. It is not easy to point out unambiguously whether or not current production systems meet this sustainability demand. A priori thinking would suggest that organic crops are environmentally favourable, but may ignore the effect of reduced productivity, which shifts the potential impact to other parts of the food provision system. The purpose of this paper is to assess the ecological sustainability of conventional and organic leek production by means of life cycle assessment (LCA). Design/methodology/approach – A cradle-to-farm gate LCA is applied, based on real farm data from two research centres. For a consistent comparison, two functional units (FU) were defined: 1ha and 1?kg of leek production. Findings – Assessed on an area basis, organic farming shows a more favourable environmental profile. These overall benefits are strongly reduced when the lower yields are taken into account. Related to organic farming it is therefore important that solutions are found to substantially increase the yields without increasing the environmental burden. Related to conventional farming, important potential for environmental improvements are in optimising the farm nutrient flows, reducing pesticide use and increasing its self-supporting capacity. Research limitations/implications – The research is a cradle-to-farm gate LCA, future research can be expanded to comprise all phases from cradle-to-grave to get an idea of the total sustainability of our present food consumption patterns. The research is also limited to the case of leek production. Future research can apply the methodology to other crops. Originality/value – To date, there is still lack of clear evidence of the added value of organic farming compared to conventional farming on environmental basis. Few studies have compared organic and conventional food production by means of LCA. This paper addresses these issues

    Towards Parameterized Regular Type Inference Using Set Constraints

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    We propose a method for inferring \emph{parameterized regular types} for logic programs as solutions for systems of constraints over sets of finite ground Herbrand terms (set constraint systems). Such parameterized regular types generalize \emph{parametric} regular types by extending the scope of the parameters in the type definitions so that such parameters can relate the types of different predicates. We propose a number of enhancements to the procedure for solving the constraint systems that improve the precision of the type descriptions inferred. The resulting algorithm, together with a procedure to establish a set constraint system from a logic program, yields a program analysis that infers tighter safe approximations of the success types of the program than previous comparable work, offering a new and useful efficiency vs. precision trade-off. This is supported by experimental results, which show the feasibility of our analysis

    Three-family oscillations using neutrinos from muon beams at very long baseline

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    The planned LBL experiments will be able to prove the hypothesis of flavor oscillation between muon and tau neutrinos. We explore the possibility of a second generation long baseline experiment at very long baseline, i.e. L in the range 5000-7000 km. This distance requires intense neutrino beams that could be available from very intense muon beams as those needed for μ\mu colliders. Such baselines allow the study of neutrino oscillations with E/L2×103eV2E/L \approx 2\times 10^{-3} eV^2 with neutrinos of energy Eν10GeVE_\nu \approx 10 GeV, i.e. above tau threshold. Moreover, matter effects inside the Earth could lead to observable effects in νeνμ\nu_e \to \nu_\mu oscillations. These effects are interchanged between neutrinos and antineutrinos, and therefore they can be tested by comparing the oscillated spectra obtained running the storage ring with positive and negative muons.Comment: 14 pages, 4 figure

    A medium baseline search for νμνe\nu_\mu\to\nu_e oscillations at a ν\nu beam from muon decays

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    The accurate knowledge of the νˉe(νμ)\bar\nu_e (\nu_\mu) beam produced in μ\mu^- decays and the absence of νe(νˉμ)\nu_e (\bar\nu_\mu) contamination, make a future muon storage ring the ideal place to look for \numunue (\numubarnuebar) oscillations. Using a detector capable of electron and muon identification with charge discrimination (e.g., the presently running NOMAD experiment), good sensitivities to \numunue (\numubarnuebar) oscillations could be achieved. With the CERN-PS as a proton driver for a muon storage ring of the kind envisaged for a μ\mu-collider, the LSND claim would be confirmed or disproved in a few years of running.Comment: 10 pages, 4 figure

    The flavor of neutrinos in muon decays at a neutrino factory and the LSND puzzle

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    The accurate prediction of the neutrino beam produced in muon decays and the absence of opposite helicity contamination for a particular neutrino flavor make a future neutrino factory the ideal place to look for the lepton flavor violating (LFV) decays of the kind \mu^+\ra e^+\nuebar\numu and lepton number violating (LNV) processes like \mu^-\ra e^-\nue\numu. Excellent sensitivities can be achieved using a detector capable of muon and/or electron identification with charge discrimination. This would allow to set experimental limits that improve current ones by more than two orders of magnitude and test the hypothesis that the LSND excess is due to such anomalous decays, rather than neutrino flavor oscillations in vacuum.Comment: 19 pages, 4 figure

    Detection of polarization from the E^4\Pi-A^4\Pi system of FeH in sunspot spectra

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    Here we report the first detection of polarization signals induced by the Zeeman effect in spectral lines of the E^4\Pi-A^4\Pi system of FeH located around 1.6 μ\mum. Motivated by the tentative detection of this band in the intensity spectrum of late-type dwarfs, we have investigated the full Stokes sunspot spectrum finding circular and linear polarization signatures that we associate with the FeH lines of the E^4\Pi-A^4\Pi band system. We investigate the Zeeman effect in these molecular transitions pointing out that in Hund's case (a) coupling the effective Land\'e factors are never negative. For this reason, the fact that our spectropolarimetric observations indicate that the Land\'e factors of pairs of FeH lines have opposite signs, prompt us to conclude that the E^4\Pi-A^4\Pi system must be in intermediate angular momentum coupling between Hund's cases (a) and (b). We emphasize that theoretical and/or laboratory investigations of this molecular system are urgently needed for exploiting its promising diagnostic capabilities.Comment: 11 pages, 4 figures, accepted for publication in Astrophysical Journal Letter

    Computational probabilistic quantification of pro-arrhythmic risk from scar and left-to-right heterogeneity in the human ventricles

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    Both scar and left-to-right ventricular (LV/RV) differences in repolarization properties have been implicated as risk factors for lethal arrhythmias. As a possible mechanism for the initiation of re-entry, a recent study has indicated that LV/RV heterogeneities in action potential duration (APD) adaptation can cause a transient increase in APD dispersion following rate acceleration, promoting unidirectional block of conduction at the LV/RV junction. In the presence of an ischemic region and ectopic stimulation, a pathological dispersion in repolarization has been suggested to increase the risk of electrical re-entry. However, the exact location and timing of the ectopic activation play a crucial role in initiation of re-entry, and certain combinations may lead to re-entry even under normal LV/RV dispersion in repolarization. This suggests that the phenomenon needs to be investigated in a quantitative way. In this study we employ a computationally efficient, phenomenological model in order to investigate the proarrhythmic properties of a range of combinations of position and timing of an ectopic activation. This allows us to probabilistically study how increasing interventricular dispersion of repolarization increases arrhythmic risk. Results indicate that a larger LV/RV dispersion in repolarization allows ectopic beats to initiate re-entry during a significantly larger time window and from a greater number of locations compared to the case of smaller LV/RV dispersion

    Issue 17: Private Sponsorship in Canada: The Resettlement of Syrian Refugees in the Kitchener-Waterloo Region

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    The number of refugees in need of resettlement in the world is estimated to surpass 1.44 million people in 2020, with Syrians currently representing 40% of refugees in need of resettlement. In late 2015, the Canadian government made a commitment to resettle 25,000 Syrian refugees and, since then, there has been abundant research analysing the large-scale resettlement process, its successes, limitations, and lessons for future policymaking and host communities. This Policy Points contributes to these analyses by unpacking the particular lessons from the Kitchener-Waterloo region, and highlighting the resettlement experiences of privately sponsored Syrian refugees in this area. It draws on policy, program, and scholarly documents, and on a selection of 55 semi-structured, in-depth interviews with mainly privately sponsored (and some government-assisted) Syrian refugees on their experiences of resettlement in southern Ontario, Canada. In this Policy Points, we emphasize that strong leadership by governments and civil society groups and organizations is crucial in the private sponsorship of Syrians, and that more policy attention and research are needed to improve the private sponsorship program in the K-W region
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