Chemical Doping of Conjugated Polymers for Thermoelectric Applications

The ongoing development of interconnected and wearable small devices, which together make up the so-called Internet of Things, is driving a rising need for autonomous and on-site energy supplies. Heat, an abundant and often wasted energy source, can be harnessed through thermoelectric generators that can directly convert heat into electricity. Small devices, such as health-monitoring sensors, may be powered by the heat dissipated from the human body using flexible thermoelectric generators made of organic semiconductors, like conjugated polymers. This thesis discusses polythiophenes with oligoether side chains, which are a promising class of conjugated polymers for the design of flexible, easily processable and light-weight thermoelectric generators. At first, this thesis investigates the solid-state order of these polymers and how is affected by varying the length of the oligoether side chains and by chemical doping with an oxidizing agent, F4TCNQ, and an acid, H-TFSI. It is showed that inducing order, either by shortening the side-chain length or by doping, enhances the transport properties of the materials, and so their thermoelectric performance.Secondly, this thesis studies the relationship between the solid-state order of these polymers and their mechanical properties. It is found that electrical and mechanical properties are usually correlated. The induced solid-state order not only improves the electrical conductivity but also enhances the stiffness of the materials. Partial decoupling of the electrical and mechanical properties is found to be possible if a suitable dopant is selected

Measuring social capital with a myograph

We study the behavior of 12 pairs of undergraduate students while they were involved in a simple coordination game requiring motor interaction. Three experimental conditions were defined according to whether a monetary prize was given to both or only one subject, if the couple was in successfully completing the required assignment. Electromyographic potentials (EMG) were recorded from the right first dorsal interosseus (FDI) muscle, a muscle critically involved in the motor task. We also collected written answers from a standard questionnaire from which we constructed individual measures of Social Capital (SC), based on organized group interaction, religious and political involvement. These measures are collected, by standard practice, to estimate individual pro-social attitudes and behavior. Consistently with our simple behavioral model, by which EMG signals are direct measures of subjects’ personal concern (call it utility) associated to the given task, our evidence shows that EMG is increasing in the subjects’ own monetary reward. When we split the subject pool into two subsamples (according to various measures of Social Capital obtained from the questionnaire), we find that monetary incentives explain the level of subjects’ EMG only in the subsample characterized by low SC, while, for subjects with (comparatively) higher SC, effort in the coordination task is much less sensitive to whether it is directly rewarded or not. This result is robust across the different SC index specifications. The present findings seem to support the possibility that an electrophysiological measure, such as EMG, could reveal the most profound attitudes and believes that guide social interaction, and that our relatively inexpensive and ready-to-use technology can back-up socio-economic research in a very effective way.NeuroEconomics; Social Capital

Editorial: How Do Motivational States Influence Motor Resonance?

status: publishe

Einstein metrics and smooth structures

We prove that there are infinitely many pairs of homeomorphic non-diffeomorphic smooth 4-manifolds, such that in each pair one manifold admits an Einstein metric and the other does not. We also show that there are closed 4-manifolds with two smooth structures which admit Einstein metrics with opposite signs of the scalar curvature.Comment: 10 pages. Published copy, also available at http://www.maths.warwick.ac.uk/gt/GTVol2/paper1.abs.htm

Measuring social capital with a myograph

We study the behavior of 12 pairs of undergraduate students while they were involved in a simple coordination game requiring motor interaction. Three experimental conditions were defined according to whether a monetary prize was given to both or only one subject, if the couple was in successfully completing the required assignment. Electromyographic potentials (EMG) were recorded from the right first dorsal interosseus (FDI) muscle, a muscle critically involved in the motor task. We also collected written answers from a standard questionnaire from which we constructed individual measures of Social Capital (SC), based on organized group interaction, religious and political involvement. These measures are collected, by standard practice, to estimate individual pro-social attitudes and behavior. Consistently with our simple behavioral model, by which EMG signals are direct measures of subjects’ personal concern (call it utility) associated to the given task, our evidence shows that EMG is increasing in the subjects’ own monetary reward. When we split the subject pool into two subsamples (according to various measures of Social Capital obtained from the questionnaire), we find that monetary incentives explain the level of subjects’ EMG only in the subsample characterized by low SC, while, for subjects with (comparatively) higher SC, effort in the coordination task is much less sensitive to whether it is directly rewarded or not. This result is robust across the different SC index specifications. The present findings seem to support the possibility that an electrophysiological measure, such as EMG, could reveal the most profound attitudes and believes that guide social interaction, and that our relatively inexpensive and ready-to-use technology can back-up socio-economic research in a very effective way.We study the behavior of 12 pairs of undergraduate students while they were involved in a simple coordination game requiring motor interaction. Three experimental conditions were defined according to whether a monetary prize was given to both or only one subject, if the couple was in successfully completing the required assignment. Electromyographic potentials (EMG) were recorded from the right first dorsal interosseus (FDI) muscle, a muscle critically involved in the motor task. We also collected written answers from a standard questionnaire from which we constructed individual measures of Social Capital (SC), based on organized group interaction, religious and political involvement. These measures are collected, by standard practice, to estimate individual pro-social attitudes and behavior. Consistently with our simple behavioral model, by which EMG signals are direct measures of subjects’ personal concern (call it utility) associated to the given task, our evidence shows that EMG is increasing in the subjects’ own monetary reward. When we split the subject pool into two subsamples (according to various measures of Social Capital obtained from the questionnaire), we find that monetary incentives explain the level of subjects’ EMG only in the subsample characterized by low SC, while, for subjects with (comparatively) higher SC, effort in the coordination task is much less sensitive to whether it is directly rewarded or not. This result is robust across the different SC index specifications. The present findings seem to support the possibility that an electrophysiological measure, such as EMG, could reveal the most profound attitudes and believes that guide social interaction, and that our relatively inexpensive and ready-to-use technology can back-up socio-economic research in a very effective way.Non-Refereed Working Papers / of national relevance onl

Hand–foot motor priming in the presence of temporary inability to use hands

To verify if the link between observed hand actions and executed foot actions found in aplasics is essentially induced by the constant use of foot substituting the hand, we investigated if the vision of a grasping hand is able to prime a foot response in normals. Participants were required to detect the time-to-contact of a hand grasping an object either with a suitable or a less suitable movement, an experimental paradigm known to induce a priming effect. Participants responded either with the hand or the foot, while having free or bound hands. Results showed that for hand responses motor priming effect was stronger when the hands were free, whereas for foot responses it was stronger when the hands were bound. These data are interpreted as a further evidence that a difficulty to move affects specific cognitive functions and that the vision of a grasping hand may prime a foot response

Efficacy of facial exercises in facial expression categorization in schizophrenia

Embodied cognition theories suggest that observation of facial expression induces the same pattern of muscle activation, and that this contributes to emotion recognition. Consequently, the inability to form facial expressions would affect emotional understanding. Patients with schizophrenia show a reduced ability to express and perceive facial emotions. We assumed that a physical training specifically developed to mobilize facial muscles could improve the ability to perform facial movements, and, consequently, spontaneous mimicry and facial expression recognition. Twenty-four inpatient participants with schizophrenia were randomly assigned to the experimental and control group. At the beginning and at the end of the study, both groups were submitted to a facial expression categorization test and their data compared. The experimental group underwent a training period during which the lip muscles, and the muscles around the eyes were mobilized through the execution of transitive actions. Participants were trained three times a week for five weeks. Results showed a positive impact of the physical training in the recognition of others' facial emotions, specifically for the responses of "fear", the emotion for which the recognition deficit in the test is most severe. This evidence suggests that a specific deficit of the sensorimotor system may result in a specific cognitive deficit

Are automatic imitation and spatial compatibility mediated by different processes?

Automatic imitation or ‘imitative compatibility’ is thought to be mediated by the mirror neuron system and to be a laboratory model of the motor mimicry that occurs spontaneously in naturalistic social interaction. Imitative compatibility and spatial compatibility effects are known to depend on different stimulus dimensions – body movement topography and relative spatial position. However, it is not yet clear whether these two types of stimulus-response compatibility effect are mediated by the same or different cognitive processes. We present an interactive activation model of imitative and spatial compatibility, based on a dual-route architecture, which substantiates the view they are mediated by processes of the same kind. The model, which is in many ways a standard application of the interactive activation approach, simulates all key results of a recent study by Catmur and Heyes (2011). Specifically, it captures the difference in the relative size of imitative and spatial compatibility effects; the lack of interaction when the imperative and irrelevant stimuli are presented simultaneously; the relative speed of responses in a quintile analysis when the imperative and irrelevant stimuli are presented simultaneously; and the different time courses of the compatibility effects when the imperative and irrelevant stimuli are presented asynchronously

Grasping the semantic of actions: a combined behavioral and MEG study

There is experimental evidence that the brain systems involved in action execution also play a role in action observation and understanding. Recently, it has been suggested that the sensorimotor system is also involved in language processing. Supporting results are slower response times and weaker motor-related MEG Beta band power suppression in semantic decision tasks on single action verbs labels when the stimulus and the motor response involve the same effector. Attenuated power suppression indicates decreased cortical excitability and consequent decreased readiness to act. The embodied approach forwards that the simultaneous involvement of the sensorimotor system in the processing of the linguistic content and in the planning of the response determines this language-motor interference effect. Here, in a combined behavioral and MEG study we investigated to what extent the processing of actions visually presented (i.e., pictures of actions) and verbally described (i.e., verbs in written words) share common neural mechanisms. The findings demonstrated that, whether an action is experienced visually or verbally, its processing engages the sensorimotor system in a comparable way. These results provide further support to the embodied view of semantic processing, suggesting that this process is independent from the modality of presentation of the stimulus, including language