6,533 research outputs found

    A digital library of language learning exercises

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    Recent years have seen widespread adoption of the Internet for language teaching and learning. Interactive systems on the World-Wide Web provide useful alternatives to face-to-face tuition, and both teachers and learners can benefit from the exercises available. However, although there is a wealth of suitable material, it is hard to find because it is scattered around the web. Moreover, teachers are restricted by the material that is available, and cannot provide their own. To tackle these problems we have constructed a digital library of language learning exercises that presents students with different kinds of exercise, and also lets teachers contribute new material. We first reviewed existing language learning systems on the web in order to develop a taxonomy of exercise types used for language activity. A prototype, ELLE, based on this taxonomy, provides various kinds of interactive exercises using material that teachers submit. The system has been evaluated by practicing language teachers

    Using pump for bypass surgery - on-off-on again?

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    Background\ud Coronary-artery bypass grafting (CABG) has traditionally been performed with the use of cardiopulmonary bypass (on-pump CABG). CABG without cardiopulmonary bypass (off-pump CABG) might reduce the number of complications related to the heart-lung machine.\ud \ud Methods\ud Objective\ud To compare off-pump to on-pump CABG in terms of short- and long-term composite of complications and death from any cause, as well as completeness and durability of the procedure/grafting, neuropsychological outcomes, and use of major resources.\ud \ud Design\ud Multi-center single-blind, randomized controlled trial.\ud \ud Setting\ud 18 Veterans Affairs medical centers, 16 of which were teaching hospitals.\ud \ud Subjects\ud 2203 patients who were scheduled for urgent or elective CABG-only procedures.\ud \ud Intervention\ud Patients were randomized to either on- or off-pump CABG. They underwent neuropsychological testing at baseline and one year, as well as follow-up angiography.\ud \ud Outcomes\ud 1) Primary short-term end-point: composite of death or major complications (reoperation, new mechanical support, cardiac arrest, coma, stroke or renal failure requiring dialysis) at discharge or day 30. 2) Primary long-term composite end-point: death from any cause within 1 year, nonfatal myocardial infarction between 30 days and 1 year, or repeat revascularization between 30 days and 1 year. 3) Secondary outcomes: completeness of revascularization, graft patency at 1 year, scores on neuropsychological tests.\ud \ud Results\ud There was no significant difference between off-pump and on-pump CABG in the rate of the 30-day composite outcome (7.0% and 5.6% respectively, P = 0.19). The rate of the 1-year composite outcome was higher for off-pump than for on-pump CABG (9.9% vs 7.4%, P = 0.04). The proportion of patients with fewer grafts completed than originally planned was higher with off-pump CABG than with on-pump CABG (17.8% vs 11.1%, P < 0.001). Follow up angiograms in 1371 patients who underwent 4093 grafts revealed that the overall rate of graft patency was lower in the off-pump group than in the on-pump group (82.6% vs. 87.8%, P < 0.01). There were no treatment-based differences in neuropsychological outcomes or short-term use of major resources..\ud \ud Conclusions\ud At 1 year of follow-up, patients in the off-pump group had worse composite outcomes and poorer graft patency than did patients in the on-pump group. No significant differences between the techniques were found in the neuropsychological outcomes or use of major resources

    First Lattice Study of the NN-P11(1440)P_{11}(1440) Transition Form Factors

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    Experiments at Jefferson Laboratory, MIT-Bates, LEGS, Mainz, Bonn, GRAAL, and Spring-8 offer new opportunities to understand in detail how nucleon resonance (N∗N^*) properties emerge from the nonperturbative aspects of QCD. Preliminary data from CLAS collaboration, which cover a large range of photon virtuality Q2Q^2 show interesting behavior with respect to Q2Q^2 dependence: in the region Q2≀1.5GeV2Q^2 \le 1.5 {GeV}^2, both the transverse amplitude, A1/2(Q2)A_{1/2}(Q^2), and the longitudinal amplitude, S1/2(Q2)S_{1/2}(Q^2), decrease rapidly. In this work, we attempt to use first-principles lattice QCD (for the first time) to provide a model-independent study of the Roper-nucleon transition form factor.Comment: 4 pages, 2 figures, double colum

    Analysis of United Kingdom Off-Highway Construction Machinery Market and Its Consumers Using New-Sales Data

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    The off-highway construction machinery market and its consumers have attracted minimal previous research. This study addresses that void by analyzing annual United Kingdom (UK) (volume/portfolio) new-sales data for the 10 most popular products within that market, 1990–2010 inclusive. Graphical, descriptive statistical, Pearson-correlational, autocorrelational, and elementary modeling are employed to identify contrasts in sales regarding (1) high- and low-volume items; (2) growth trends and significant recessionary effects on volumes; (3) a demand change point circa 1997, since when annual product portfolio has changed little; and (4) product associations in consumer demand. Significant association is demonstrated between demand and construction output, especially with the value of new housing. Subsequently, consumption of wheeled loaders is modeled using construction volume, and demand for mini and crawler excavators is modeled using new-housing data. Time series trends for these machinery types are presented and forecast through 2015. The primary contribution of this study is a deeper understanding of the UK new-machinery market and the predilections of its consumers over the last two decades (to present)

    Force distributions in a triangular lattice of rigid bars

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    We study the uniformly weighted ensemble of force balanced configurations on a triangular network of nontensile contact forces. For periodic boundary conditions corresponding to isotropic compressive stress, we find that the probability distribution for single-contact forces decays faster than exponentially. This super-exponential decay persists in lattices diluted to the rigidity percolation threshold. On the other hand, for anisotropic imposed stresses, a broader tail emerges in the force distribution, becoming a pure exponential in the limit of infinite lattice size and infinitely strong anisotropy.Comment: 11 pages, 17 figures Minor text revisions; added references and acknowledgmen

    Accountability, Strategy, and International Non-Governmental Organizations

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    Increased prominence and greater influence expose international non-governmental development and environmental organizations (INGOs) to increased demands for accountability from a wide variety of stakeholdersdonors, beneficiaries, staffs, and partners among others. This paper focuses on developing the concept of INGO accountability, first as an abstract concept and then as a strategic idea with very different implications for different INGO strategies. We examine those implications for INGOs that emphasize service delivery, capacity-building, and policy influence. We propose that INGOs committed to service delivery may owe more accountability to donors and service regulators; capacity-building INGOs may be particularly obligated to clients whose capacities are being enhanced; and policy influence INGOs may be especially accountable to political constituencies and to influence targets. INGOs that are expanding their activities to include new initiatives may need to reorganize their accountability systems to implement their strategies effectively. This publication is Hauser Center Working Paper No. 7. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers

    Psychiatric Manifestation of Vitamin B-12 Deficiency: An Update

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    Psychiatric manifestations of vitamin B-12 deficiency are reviewed from 1986 to the present. Specific clinical entities reviewed include depression, organic psychosis, obsessive-compulsive disorder, childhood manifestations and dementia. We recommend that consideration be given to B-12 deficiency as an etiological factor in some cases of depression, organic psychosis, certain childhood disorders and dementia. Routine screening of people overage 65 is addressed

    Interacting Crumpled Manifolds: Exact Results to all Orders of Perturbation Theory

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    In this letter, we report progress on the field theory of polymerized tethered membranes. For the toy-model of a manifold repelled by a single point, we are able to sum the perturbation expansion in the strength g of the interaction exactly in the limit of internal dimension D -> 2. This exact solution is the starting point for an expansion in 2-D, which aims at connecting to the well studied case of polymers (D=1). We here give results to order (2-D)^4, where again all orders in g are resummed. This is a first step towards a more complete solution of the self-avoiding manifold problem, which might also prove valuable for polymers.Comment: 8 page

    Global agricultural intensification during climate change: a role for genomics

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    Agriculture is now facing the ‘perfect storm’ of climate change, increasing costs of fertilizer and rising food demands from a larger and wealthier human population. These factors point to a global food deficit unless the efficiency and resilience of crop production is increased. The intensification of agriculture has focused on improving production under optimized conditions, with significant agronomic inputs. Furthermore, the intensive cultivation of a limited number of crops has drastically narrowed the number of plant species humans rely on. A new agricultural paradigm is required, reducing dependence on high inputs and increasing crop diversity, yield stability and environmental resilience. Genomics offers unprecedented opportunities to increase crop yield, quality and stability of production through advanced breeding strategies, enhancing the resilience of major crops to climate variability, and increasing the productivity and range of minor crops to diversify the food supply. Here we review the state of the art of genomic-assisted breeding for the most important staples that feed the world, and how to use and adapt such genomic tools to accelerate development of both major and minor crops with desired traits that enhance adaptation to, or mitigate the effects of climate chang
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