Methodological issues in measures of imitative reaction times

Ideomotor (IM) theory suggests that observing someone else perform an action activates an internal motor representation of that behaviour within the observer. Evidence supporting the case for an ideomotor theory of imitation has come from studies that show imitative responses to be faster than the same behavioural measures performed in response to spatial cues. In an attempt to replicate these findings, we manipulated the salience of the visual cue and found that we could reverse the advantage of the imitative cue over the spatial cue. We suggest that participants utilised a simple visuomotor mechanism to perform all aspects of this task, with performance being driven by the relative visual salience of the stimuli. Imitation is a more complex motor skill that would constitute an inefficient strategy for rapid performance

Constrained action selection in children with developmental coordination disorder

The effect of advance (‘precue’) information on short aiming movements was explored in adults, high school children, and primary school children with and without developmental coordination disorder (n = 10, 14, 16, 10, respectively). Reaction times in the DCD group were longer than in the other groups and were more influenced by the extent to which the precue constrained the possible action space. In contrast, reaction time did not alter as a function of precue condition in adults. Children with DCD showed greater inaccuracy of response (despite the increased RT). We suggest that the different precue effects reflect differences in the relative benefits of priming an action prior to definitive information about the movement goal. The benefits are an interacting function of the task and the skill level of the individual. Our experiment shows that children with DCD gain a benefit from advance preparation in simple aiming movements, highlighting their low skill levels. This result suggests that goal-directed RTs may have diagnostic potential within the clinic

Optimisation in behavioural synthesis using hierarchical expansion: module ripping

During behavioural synthesis, an abstract functional description of a system is mapped automatically onto a physical structure. In a competitive setting, this mapping will be highly optimised - the dataflow is re-arranged, units and registers are multiplexed and so on - to deliver a final structure that meets some overall user supplied specification. Ultimately, however, the physical functional units are drawn from some predefined (human designed) library - these may be thought of as the leaf-level modules in the design hierarchy. Design re-use and increasing sophistication of module libraries inevitably leads to leaf modules becoming larger and more complex. As these modules are, by definition, atomic, a synthesis system is unable to capitalise on any internal similarities the leaf modules may possess. This paper describes the design, construction and effects of using a hierarchically defined module library. The set of leaf-level modules made available to the synthesis environment is conventional - add, subtract, multiply and so on - but the optimiser is capable of ?ripping apart? these modules to manipulate their inner structures. Two advantages accrue from this technique: (1) it is possible to optimise behavioural designs far more effectively, with up to a 65% reduction in area, and a 46% reduction in delay reported, and (2) it is possible to build library modules that have tightly controllable internal timing relationships. This is essential when designing systems that communicate externally via low-level protocols, but behavioural synthesis, by its very nature, usually distorts timing information. Using this technique, it is possible to create ?islands of fixed timing? embedded in the synthesised design

Simultaneous Optimisation of Dynamic Power, Area and Delay in Behavioural Synthesis

Concern over power dissipation coupled with the continuing rise in system size and complexity means that there is a growing need for high-level design tools capable of automatically optimising systems to take into account power dissipation, in addition to the more conventional metrics of area, delay and testability. Current methods for reducing power consumption tend to be ad-hoc: for example, slowing down, or turning off idle parts of the system, or a controlled reduction in power supply. The behavioural synthesis system described in this paper features an integrated incremental power estimation capability, which makes use of activity profiles, generated automatically through simulation of a design on any standard VHDL simulator; accurate circuit-level cell models (generated, again automatically, via Spice simulation); and a comprehensive system power model. This data, along with similar estimators for area and delay, guides the optimisation of a design towards independent, user-specified objectives for final area, delay, clock speed, and energy consumption. In addition, a range of power reducing features are included encompassing: supply voltage scaling, clock gating, input latching, input gating, low-power cells, and pipelined and multicycle units. These are automatically exploited during optimisation as part of the area/delay/power dissipation trade-off process. The resulting system is capable of reducing the estimated energy consumption of several benchmark designs by factors of between 3.5 and 7.0 times. Furthermore, the design exploration capability enables a range of alternative structural implementations to be generated from a single behavioural description, with differing area/delay/power trade-offs

Оборудование для испытания листовых конструкционных материалов при двухосном растяжении. Сообщение 1. Испытания односторонним давлением рабочей среды

Рассмотрены конструктивные особенности оборудования для исследования прочности и закономерностей разрушения листовых конструкционных материалов при двухосном растяжении путем нагружения образцов односторонним давлением рабочей среды. Предложены решения ряда проблем методического характера, связанных с испытаниями при высоких уровнях давления рабочей среды, что позволяет обеспечить необходимые режимы охлаждения образцов, снизить уровень энергии разрушения, повысить надежность и безопасность испытаний.Розглянуто конструктивні особливості устаткування для дослідження міцності і закономірностей руйнування листових конструкційних матеріалів при двовісному розтязі зразків одностороннім тиском робочого середовища. Запропоновано рішення ряду проблем методичного характеру, що пов’язані з випробуваннями при високих рівнях тиску робочого середовища. Це дозволить забезпечити необхідні режими охолодження зразків, знизити рівень енергії руйнування, підвищити надійность та безпеку випробувань.Design features of the equipment for studying strength and regularities of fracture of sheet structural materials in biaxial tension by subjecting specimens to one-sided pressure of a working medium are considered. Solutions were suggested for a number of methodological problems related to testing at high levels of pressure of a working medium. These solutions make it possible to provide necessary conditions of cooling of specimens, lower the level of fracture energy, and improve reliability and safety of the tests

Intact automatic avoidance of obstacles in patients with visual form agnosia

In everyday life our reaching behaviour has to be guided not only by the location and properties of the target object, but also by the presence of potential obstacles in the workspace. Recent evidence from neglect and optic ataxia patients has suggested that this automatic obstacle avoidance is mediated by the dorsal, rather than the ventral, stream of visual processing. We tested this idea in two studies involving patients with visual form agnosia resulting from bilateral ventral-stream damage. In the first study, we asked patient DF to reach out and pick up a target object in the presence of obstacles placed at varying distances to the left or right of the target. We found that both DF and controls shifted their trajectories away from the potential obstacles and adjusted their grip aperture in such a way as to minimize risk of collision. In a second study, we asked DF and a second patient, SB, to either reach between, or to bisect the space between, two cylinders presented at varying locations. We found that both patients adjusted their reach trajectories to account for shifts in cylinder location in the reaching task, despite showing significantly worse performance than control subjects when asked to make a bisection judgement. Taken together, these data indicate that automatic obstacle avoidance behaviour is spared in our patients with visual form agnosia. We attribute their ability to the functional intactness of the dorsal stream of visual processing, and argue that the ventral stream plays no important role in automatic obstacle avoidance

Effects of the Congo Basin Rainforest on Rainfall Patterns

Large-scale deforestation in the Congo Basin has an impact on rainfall patterns, both in the Basin and beyond. Factors like socio-economic drivers contribute to ongoing deforestation, and forest loss rates are expected to increase. The mechanisms linking deforestation and rainfall are complex. On a local scale, deforested areas might experience increased rainfall, but adjacent forests could see reduced rainfall. On larger scales, widespread deforestation can reduce overall rainfall in large areas. These changes can impact agriculture, with delayed rainfall and shorter rainy seasons affecting crop yields. By 2100, projected forest loss in the Congo Basin may reduce annual rainfall by 8-10%. However, uncertainties remain due to limited data and understanding of rainfall drivers and interactions in the region

Adult beginner distance language learner perceptions and use of assignment feedback

This qualitative study examines perceptions and use of assignment feedback among adult beginner modern foreign language learners on higher education distance learning courses. A survey of responses to feedback on assignments by 43 Open University students on beginner language courses in Spanish, French, and German indicated that respondents can be classified into three groups: those who use feedback strategically by integrating it into the learning process and comparing it with, for example, informal feedback from interaction with native speakers, those who take note of feedback, but seem not to use it strategically, and those who appear to take little account of either marks or feedback. The first group proved to be the most confident and most likely to maintain their motivation in the longer term. The conclusion discusses some of the pedagogical and policy implications of the findings