961 resultados para Clean hands


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In a semi-naturalistic response-effect compatibility paradigm, participants were given the opportunity to learn that hand-shaking actions would be followed by social effects (human hand-shaking stimuli from a third-person perspective) or inanimate effects (block arrow stimuli). Relative to the actions, these effects appeared on the same or the opposite side of the screen (positional compatibility), and pointed towards or away from the response hand (directional compatibility). After learning, response times indicated a positional compatibility effect for both social and inanimate effects, but a directional compatibility effect occurred only for social action effects. These findings indicate that actions can be represented, not only by their effects on the inanimate world, but also by their effects on the actions of others. They are consistent with ideomotor theory, and with the view that actions are represented by bidirectional response-effect associations. They also have implications with respect to the origins and on-line control of imitation and the systems supporting imitation.

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The adsorption of NO on Ir{100} has been studied as a function of NO coverage and temperature using temperature programmed reflection absorption infrared spectroscopy (TP-RAIRS), low energy electron diffraction (LEED) and temperature programmed desorption (TPD). After saturating the clean (1 x 5)-reconstructed surface with NO at 95 K. two N-2, desorption peaks are observed upon heating. The first N-2 peak at 346 K results from the decomposition of bridge-bonded NO, and the second at 475 K from the decomposition of atop-bonded NO molecules. NO decomposition is proposed to be the rate limiting step for both N-2 desorption states. For high NO coverages on the (1 x 5) surface, the narrow width of the first N-2 desorption peak is indicative of an autocatalytic process for which the parallel formation of N2O appears to be the crucial step. When NO is adsorbed on the metastable unreconstructed (1 x 1) phase of clean Ir{100} N-2 desorption starts at lower temperatures, indicating that this surface modification is more reactive. When a high coverage of oxygen, near 0.5 ML, is pre-adsorbed on the surface, the decomposition of NO is inhibited and mainly desorption of intact NO is observed.

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Recently a substantial amount of research has been done in the field of dextrous manipulation and hand manoeuvres. The main concern has been how to control robot hands so that they can execute manipulation tasks with the same dexterity and intuition as human hands. This paper surveys multi-fingered robot hand research and development topics which include robot hand design, object force distribution and control, grip transform, grasp stability and its synthesis, grasp stiffness and compliance motion and robot arm-hand coordination. Three main topics are presented in this article. The first is an introduction to the subject. The second concentrates on examples of mechanical manipulators used in research and the methods employed to control them. The third presents work which has been done on the field of object manipulation.

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Manipulation of an object by a multi-fingered robot hand requires task planning which involves computation of joint space vectors and fingertip forces. To implement a task as fast as possible, computations have to be carried out in minimum time. The state of the art in manipulation by multi-fingered robot hand designs has shown the possible use of remotely driven finger joints. Such remotely driven hands require computation of tendon displacement for evaluating joint space vectors before signals are sent to actuators. Alternatively, a direct drive hand is a mechanical hand in which the shafts of articulated joints are directly coupled to the rotors of motors with high output torques. This article has been divided into two main sections. The first section presents a brief view of manipulation using a direct drive approach. Meanwhile, the other section presents ongoing research which is being carried out to design a four-finger articulated hand in the Department of Cybernetics at the University of Reading.

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We studied how the integration of seen and felt tactile stimulation modulates somatosensory processing, and investigated whether visuotactile integration depends on temporal contiguity of stimulation, and its coherence with a pre-existing body representation. During training, participants viewed a rubber hand or a rubber object that was tapped either synchronously with stimulation of their own hand, or in an uncorrelated fashion. In a subsequent test phase, somatosensory event-related potentials (ERPs) were recorded to tactile stimulation of the left or right hand, to assess how tactile processing was affected by previous visuotactile experience during training. An enhanced somatosensory N140 component was elicited after synchronous, compared with uncorrelated, visuotactile training, irrespective of whether participants viewed a rubber hand or rubber object. This early effect of visuotactile integration on somatosensory processing is interpreted as a candidate electrophysiological correlate of the rubber hand illusion that is determined by temporal contiguity, but not by pre-existing body representations. ERPmodulations were observed beyond 200msec post-stimulus, suggesting an attentional bias induced by visuotactile training. These late modulations were absent when the stimulation of a rubber hand and the participant’s own hand was uncorrelated during training, suggesting that pre-existing body representations may affect later stages of tactile processing.

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The brain keeps track of the changing positions of body parts in space using a spatial body schema. When subjects localise a tactile stimulus on the skin, they might either use a somatotopic body map, or use a body schema to identify the location of the stimulation in external space. Healthy subjects were touched on the fingertips, with the hands in one of two postures: either the right hand was vertically above the left, or the fingers of both hands were interwoven. Subjects made speeded verbal responses to identify either the finger or the hand that was touched. Interweaving the fingers significantly impaired hand identification across several experiments, but had no effect on finger identification. Our results suggest that identification of fingers occurs in a somatotopic representation or finger schema. Identification of hands uses a general body schema, and is influenced by external spatial location. This dissociation implies that touches on the finger can only be identified with a particular hand after a process of assigning fingers to hands. This assignment is based on external spatial location. Our results suggest a role of the body schema in the identification of structural body parts from touch.

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This paper examines the ethics of the Clean Development Mechanism (CDM) in its architecture, processes and outcomes and its potential to allocate resources to the poor as ‘ethical development’. Two specific examples of CDM projects help us to explore some of the quandaries that seem to be quickly defining operating procedure for the CDM in its efforts to bring entitlementsto the poor. The paper concludes with reflections on the normative and social complications of the CDM and closes with three key areas of further investigation.

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The rate and magnitude of predicted climate change require that we urgently mitigate emissions or sequester carbon on a substantial scale in order to avoid runaway climate change. Geo- and bioengineering solutions are increasingly proposed as viable and practical strategies for tackling global warming. Biotechnology companies are already developing transgenic “super carbon-absorbing” trees, which are sold as a cost-effective and relatively low-risk means of sequestering carbon. The question posed in this article is, Do super carbon trees provide real benefits or are they merely a fanciful illusion? It remains unclear whether growing these trees makes sense in terms of the carbon cost of production and the actual storage of carbon. In particular, it is widely acknowledged that “carbon-eating” trees fail to sequester as much carbon as they oxidize and return to the atmosphere; moreover, there are concerns about the biodiversity impacts of large-scale monoculture plantations. The potential social and ecological risks and opportunities presented by such controversial solutions warrant a societal dialogue.

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Global agreements have proliferated in the past ten years. One of these is the Kyoto Protocol, which contains provisions for emissions reductions by trading carbon through the Clean Development Mechanism (CDM). The CDM is a market-based instrument that allows companies in Annex I countries to offset their greenhouse gas emissions through energy and tree offset projects in the global South. I set out to examine the governance challenges posed by the institutional design of carbon sequestration projects under the CDM. I examine three global narratives associated with the design of CDM forest projects, specifically North – South knowledge politics, green developmentalism, and community participation, and subsequently assess how these narratives match with local practices in two projects in Latin America. Findings suggest that governance problems are operating at multiple levels and that the rhetoric of global carbon actors often asserts these schemes in one light, while the rhetoric of those who are immediately involved locally may be different. I also stress the alarmist’s discourse that blames local people for the problems of environmental change. The case studies illustrate the need for vertical communication and interaction and nested governance arrangements as well as horizontal arrangements. I conclude that the global framing of forests as offsets requires better integration of local relationships to forests and their management and more effective institutions at multiple levels to link the very local to the very large scale when dealing with carbon sequestration in the CDM.

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We studied the effect of tactile double simultaneous stimulation (DSS) within and between hands to examine spatial coding of touch at the fingers. Participants performed a go/no-go task to detect a tactile stimulus delivered to one target finger (e.g., right index), stimulated alone or with a concurrent non-target finger, either on the same hand (e.g., right middle finger) or on the other hand (e.g., left index finger=homologous; left middle finger=non-homologous). Across blocks we also changed the unseen hands posture (both hands palm down, or one hand rotated palm-up). When both hands were palm-down DSS interference effects emerged both within and between hands, but only when the non-homologous finger served as non-target. This suggests a clear segregation between the fingers of each hand, regardless of finger side. By contrast, when one hand was palm-up interference effects emerged only within hand, whereas between hands DSS interference was considerably reduced or absent. Thus, between hands interference was clearly affected by changes in hands posture. Taken together, these findings provide behavioral evidence in humans for multiple spatial coding of touch during tactile DSS at the fingers. In particular, they confirm the existence of representational stages of touch that distinguish between body-regions more than body-sides. Moreover, they show that the availability of tactile stimulation side becomes prominent when postural update is required.

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Final year research projects are an important part of undergraduate chemistry courses, allowing students to enhance transferable skills in teamworking, problem solving and presentations, at the same time as learning valuable practical skills. Several recent reports have highlighted the importance of research based studies as part of undergraduate courses. ‘We need to encourage universities to explore new models of curriculum. They should all incorporate research based study for undergraduates to cultivate awareness of research careers, to train students in research skills for employment, and to sustain the advantages of a research teaching connection,’ wrote Paul Ramsden from James Cook University, Australia, in a 2008 report for the UK’s Higher Education Academy.1 A 2010 report published by the Biopharma Skills Consortium – that promotes collaboration across the higher education sector in the area of biopharma – also stated that: ‘Companies seek recruits well placed to acclimatise quickly to the work environment. They are looking for recruits who can deploy a range of generic skills in the application of their knowledge.’2

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Detection of a tactile stimulus on one finger is impaired when a concurrent stimulus (masker) is presented on an additional finger of the same or the opposite hand. This phenomenon is known to be finger-specific at the within-hand level. However, whether this specificity is also maintained at the between-hand level is not known. In four experiments, we addressed this issue by combining a Bayesian adaptive staircase procedure (QUEST) with a two-interval forced choice (2IFC) design in order to establish threshold for detecting 200ms, 100Hz sinusoidal vibrations applied to the index or little fingertip of either hand (targets). We systematically varied the masker finger (index, middle, ring, or little finger of either hand), while controlling the spatial location of the target and masker stimuli. Detection thresholds varied consistently as a function of the masker finger when the latter was on the same hand (Experiments 1 and 2), but not when on different hands (Experiments 3 and 4). Within the hand, detection thresholds increased for masker fingers closest to the target finger (i.e., middle>ring when the target was index). Between the hands, detection thresholds were higher only when the masker was present on any finger as compared to when the target was presented in isolation. The within hand effect of masker finger is consistent with the segregation of different fingers at the early stages of somatosensory processing, from the periphery to the primary somatosensory cortex (SI). We propose that detection is finger-specific and reflects the organisation of somatosensory receptive fields in SI within, but not between the hands.