2,124 research outputs found

    Hand to mouth: automatic imitation across effector systems

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    The effector-specificity of automatic imitation was investigated using a stimulus-response compatibility (SRC) procedure in which participants were required to make an open or a close response with either their hand or their mouth. The correct response for each trial was indicated by a pair of letters, and each of these imperative stimuli was accompanied by task-irrelevant action images depicting a hand or mouth opening or closing. Relative to the response, the irrelevant stimulus was either movement compatible or movement incompatible, and either effector compatible or effector incompatible. A movement compatibility effect was observed for both hand and mouth responses. These movement compatibility effects were present when the irrelevant stimulus was effector compatible and when it was effector incompatible, but they were smaller when the irrelevant stimulus and response effectors were incompatible. These findings, which are consistent with the associative sequence learning model of imitation, indicate that automatic imitation is partially effector-specific, and therefore that the effector specificity of intentional and instructed imitation reflects, at least in part, the nature of the mechanisms that mediate visuomotor translation for imitation

    Time course analyses confirm independence of automatic imitation and spatial compatibility effects

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    Automatic imitation has been used as a behavioural index of the functioning of the human mirror system (e.g. Brass, Bekkering, Wohlschlager, & Prinz, 2000; Heyes, Bird, Johnson, & Haggard, 2005; Kilner, Paulignan, & Blakemore, 2003). However, several papers have criticised the assumption that automatic imitation is mediated by the mirror system on the grounds that automatic imitation has been confounded with simple spatial compatibility (Aicken, Wilson, Williams, & Mon-Williams, 2007; Bertenthal, Longo, and Kosobud, 2006; Jansson, Wilson, Williams, & Mon-Williams, 2007). Two experiments are reported in which, in contrast with previous studies, automatic imitation was measured on both spatially compatible and spatially incompatible trials, and automatic imitation was shown to be present regardless of spatial compatibility. Additional features of the two experiments allowed measurement of the time courses of the automatic imitation and spatial compatibility effects both within and across trials. It was found that automatic imitation effects follow a different time course from spatial compatibility effects, providing further evidence for their independence and supporting the use of automatic imitation as a behavioural marker of mirror system functioning

    Actions speak louder than words: comparing automatic imitation and verbal command

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    Automatic imitation – copying observed actions without intention – is known to occur, not only in neurological patients and those with developmental disorders, but also in healthy, typically-developing adults and children. Previous research has shown that a variety of actions are automatically imitated, and that automatic imitation promotes social affiliation and rapport. We assessed the power of automatic imitation by comparing it with the strength of the tendency to obey verbal commands. In a Stroop interference paradigm, the stimuli were compatible, incompatible and neutral compounds of hand postures and verbal commands. When imitative responses were required, the impact of irrelevant action images on responding to words was greater than the effect of irrelevant words on responding to actions. Control group performance showed that this asymmetry was not due to modality effects or differential salience of action and word stimuli. These results indicate that automatic imitation was more powerful than verbal command

    Towards a Simplified Model to Describe Ozone Formation in Europe

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    Air pollution is a multi-faceted problem with a variety of pollutants released from a large number of different anthropogenic activities causing a multitude of environmental effects. Cost-effective strategies to reduce negative impacts of air pollution must take account of these complexities and consider the individual aspects of the air pollution problem simultaneously. Integrated assessment models provide a consistent framework for a systematic analysis of alternative strategies. One of such models, the RAINS (Regional Acidification Information and Simulation) model developed at IIASA, has been used as a scientific support tool for the international discussions on further reductions of emissions of sulfur dioxide in Europe, which led in 1994 to an agreement on the 'Second Sulfur Protocol'. The perceived success of this agreement motivated further work on extending model analysis to additional pollutants and effects. Elevated levels of tropospheric ozone are currently considered as one of the major air quality problems in Europe, calling for balanced reductions of emissions of nitrogen oxides and volatile organic compounds. A major obstacle for developing a practical integrated assessment model for ozone is the complexity and the size of most of the current models on atmospheric ozone formation. This paper tries to identify elements for potential model simplifications, which could contribute to the development of an operational European-scale ozone formation model. Such a simplified model would establish the core of an integrated assessment model for ozone formation, linking information on emissions and emission control costs with an assessment of their environmental impacts

    Baby steps: investigating the development of perceptual-motor couplings in infancy

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    There are cells in our motor cortex that fire both when we perform and when we observe similar actions. It has been suggested that these perceptual-motor couplings in the brain develop through associative learning during correlated sensorimotor experience. Although studies with adult participants have provided support for this hypothesis, there is no direct evidence that associative learning also underlies the initial formation of perceptual–motor couplings in the developing brain. With the present study we addressed this question by manipulating infants’ opportunities to associate the visual and motor representation of a novel action, and by investigating how this influenced their sensorimotor cortex activation when they observed this action performed by others. Pre-walking 7–9-month-old infants performed stepping movements on an infant treadmill while they either observed their own real-time leg movements (Contingent group) or the previously recorded leg movements of another infant (Non-contingent control group). Infants in a second control group did not perform any steps and only received visual experience with the stepping actions. Before and after the training period we measured infants’ sensorimotor alpha suppression, as an index of sensorimotor cortex activation, while they watched videos of other infants’ stepping actions. While we did not find greater sensorimotor alpha suppression following training in the Contingent group as a whole, we nevertheless found that the strength of the visuomotor contingency experienced during training predicted the amount of sensorimotor alpha suppression at post-test in this group. We did not find any effects of motor experience alone. These results suggest that the development of perceptual–motor couplings in the infant brain is likely to be supported by associative learning during correlated visuomotor experience

    The RAINS Optimization Module for the Clean Air For Europe (CAFE) Programme

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    In 2005 the European Commission developed the Thematic Strategy on Air Quality (COM (2005) 446). IIASA's TAP programme has been instrumental in preparing various emission scenarios for the development of the strategy, and the optimization module of RAINS has been used extensively in the exercise. In this report we document the mathematical formulation and methodological aspects of the optimization module of RAINS

    The GAINS Optimization Module: Identifying Cost-effective Measures for Improving Air Quality and Short-term Climate Forcing

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    This document describes the optimization framework of the GAINS model as used for the development of cost-effective air pollution control scenarios for Europe. We put particular emphasis on the methodology for finding cost-effective control strategies that address both environmental impact indicators related to air pollution, and the radiative forcing of (some of) these pollutants. The GAINS multi-pollutant multi-effect framework lends itself for analysing synergies and trade-offs between different objectives and for quantifying cost implications. In this document we describe various formal aspects of the optimization, including the dimension of the solution space, nature and use of decision variables and their relation to relevant functions, such as cost, emissions and environmental impact indicators. We illustrate standard optimization configurations that are used to calculate commonly used scenarios. We introduce the gap closure procedure that allows to set targets that are guaranteed to be feasible and which at the same time respect the need to distribute environmental benefits evenly, as far as possible, between countries. We further illustrate, for selected ambition levels, the trade-off between reductions in environmental impact indicators and radiative forcings. Within certain ranges, these trade-offs in terms of physical effects can be compensated by changing to a more costly control strategy. The cost for compensation can systematically be calculated, and very specific recommendations can be made in terms of measures in different countries. Unlike in multi-criteria optimization the current formulation of the GAINS optimization makes very explicit the distinction between environmental objectives and control costs. Thus, judgements about the relative value of various environmental benefits are not hidden in some model assumption but need to be made explicit and open in view of the results. In this way, GAINS can be used to aid policy makers to contemplate policy options with the required flexibility, without losing sight of cost-effectiveness considerations

    A spectroscopic cell for fast pressure jumps across the glass transition line

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    We present a new experimental protocol for the spectroscopic study of the dynamics of glasses in the aging regime induced by sudden pressure jumps (crunches) across the glass transition line. The sample, initially in the liquid state, is suddenly brought in the glassy state, and therefore out of equilibrium, in a four-window optical crunch cell which is able to perform pressure jumps of 3 kbar in a time interval of ~10 ms. The main advantages of this setup with respect to previous pressure-jump systems is that the pressure jump is induced through a pressure transmitting fluid mechanically coupled to the sample stage through a deformable membrane, thus avoiding any flow of the sample itself in the pressure network and allowing to deal with highly viscous materials. The dynamics of the sample during the aging regime is investigated by Brillouin Light Scattering (BLS). For this purpose the crunch cell is used in conjunction with a high resolution double monochromator equipped with a CCD detector. This system is able to record a full spectrum of a typical glass forming material in a single 1 s shot. As an example we present the study of the evolution toward equilibrium of the infinite frequency longitudinal elastic modulus (M_infinity) of a low molecular weight polymer (Poly(bisphenol A-co-epichlorohydrin), glycidyl end capped). The observed time evolution of M_infinity, well represented by a single stretched exponential, is interpreted within the framework of the Tool-Narayanaswamy theory.Comment: 9 pages, 11 figure

    Co-benefits of post-2012 global GHG-mitigation policies

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    This report provides an analysis of the impact of global greenhouse gas policies on traditional air pollutants using the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model in the time horizon up to 2050. The integrated assessment framework of GAINS has been linked through an interface to the POLES global energy system model so that different global energy pathways can be implemented and examined. The impact analysis has been carried out based on projections of energy use data provided by the POLES model for two different climate policy scenarios, i.e., for a current policy Baseline scenario without any global greenhouse gas mitigation efforts, and a 2-degree Centigrade climate Mitigation scenario which assumes internationally coordinated action to mitigate climate change. Outcomes of the analysis are reported globally and for key world regions: EU-27, China, India and the US. The assessment takes into account current air pollution control legislation in each country. The results of scenario calculations for SO2, NOx and PM2.5 emissions, air pollution control costs, as well as health and environmental impacts, indicate significant scope for co-benefits made possible through climate policies. Climate mitigation measures appear to be more effective in reducing oxides of sulphur and nitrogen, while emissions of particulate matter are reduced to a smaller extent. Decarbonisation of the global energy system by 2050 results in SO2 and NOx emissions lower by two-thirds than in the world without GHG-abatement efforts. Corresponding reduction in the emissions of PM2.5 is estimated at about 30% relative to the Baseline and is particularly sensitive to the assumptions on projected biomass combustion. Expenditures on air pollution control under the global climate mitigation regime are reduced in 2050 by 250 billion Euros when compared to the Baseline scenario. Under the GAINS cost assumptions the largest potential for cost savings is reported for the transport sector, followed by savings in the power generation sector. Around one third of financial co-benefits estimated world-wide in this study by 2050 are allocated to China, while an annual cost saving of 35 billion Euros is estimated for the EU member countries if the current air pollution legislation and climate policies are adopted in parallel. This study also quantifies health impacts of air pollution in Europe, China and India in terms of loss of life expectancy related to the exposure from anthropogenic emissions of PM2.5, as well as in terms of premature mortality due to ground-level ozone. For example in China, current ambient concentrations of PM2.5 are responsible for 38 months-losses in the average life expectancy. In 2050, the global GHG-mitigating strategies reduce this indicator in China by 16 months. In addition, decrease of ozone concentrations in the three regions as estimated for the climate Mitigation scenario in 2050 might save nearly 80,000 cases of premature death per year. Similarly significant are reductions of impacts on ecosystems due to acidification and eutrophication
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