Action execution and recognition: a neuropsychological analysis

Humans appear to show an innate tendency to imitate, and this may provide one of the foundations of social communication. Several studies have been carried out in social and cognitive science in order to understand how imitation works, which parts of the brain are involved, and what the role of imitation might be in social behaviour. Previous brain imaging and neuropsychological studies report data that favour a dual process account of imitation, according to which actions are imitated through different mechanisms on the basis of whether they are meaningful and familiar (MF actions) or meaningless/unfamiliar (ML actions). However many questions remain to be clarified – such as which brain areas mediate these different actions. In addition to the distinction between MF and ML gestures, there is considerable interest in the production of different types of known gestures – particularly between actions involving tools (i.e. transitive actions) and those subserving communicative (intransitive) gestures, and in how the production of these gestures relates to the processes involved in recognizing the gestures as input. This thesis reports a neuropsychological examination of the functional and neural bases of imitation using converging data from behavioural studies with different patient groups (stroke patients, patients with Parkinson’s Disease, PD) and structural brain imaging (particularly using voxel-based morphometric [VBM] analyses) to examine lesion-symptom relations. The first empirical chapter (Chapter 2) describes a neuropsychological study on the recognition and production of MF actions and the imitation of ML gestures, in patients with unilateral left or rightside brain damage (respectively: LBD and RBD patients). At a group level, LBD patient were worse in imitation than RBD patients only when novel transitive actions had to be reproduced, when both LBD and RBD differed from healthy participants, while intransitive gestures were generally easier to be executed. Also both transitive and intransitive action imitation tasks were correlated to action recognition. At a single subject level, however, there was evidence for some dissociated symptoms, suggesting that at least partially different mechanisms mediate the imitation of transitive and intransitive gestures and gesture production as opposed to recognition. Chapter 3 presents a first attempt to use VBM to evaluate the relations between brain lesions and the symptoms of apraxia, contrasting the imitation of meaningful (familiar) and meaningless (unfamiliar) transitive and intransitive actions in a consecutive series of brain damaged patients. Chapters 4 and 5 describe two investigations where VBM was again used in a large-scale lesionsymptom analysis of deficits in i) the recognition and generation to command of MF actions and the imitation of ML actions, and ii) the generation to command of different types of learned action (transitive or intransitive gestures). All three investigations using VBM revealed common and differential neural substrates involved in the execution of the tasks considered, and the data are compatible with a model which posits that different processes are involved in MF and ML action execution, as well as in action understanding. The results also suggest that the distinction between transitive and intransitive actions may be included in an action reproduction system. In the final empirical chapter (Chapter 6), I report a study on PD patients tested for imitation of transitive and intransitive MF and ML actions, also relating their performance to the neurological/peripheral symptoms of the disease. This study revealed that PD patients were impaired in imitation, and they also had different pattern of deficit for transitive and intransitive actions. The correlation with peripheral symptoms was not significant, though there were correlations with underlying cognitive processes likely to support action production. Chapter 7 summarizes the different results and links them back to functional and neural accounts of action recognition, production and imitation. The relations between action production and recognition and other cognitive processes are discussed, as are methodological issues concerning lesion-symptom mapping

State and parameter estimation approach to monitoring AGR nuclear core

This work concerns with the problem of monitoring an Advanced Gas-cooled Nuclear Reactor (AGR) core. This plant (figure 1) makes use of the heat given by the nuclear efficient reaction to produce electricity by means of steam turbines. These are driven by steam, which is heated, from the AGR gas using a heat exchanger. One of the advantages of a gas cooled reactor is the high temperature that the gas can achieve so that when it is used in conjunction with the heat exchanger and steamed turbine the thermal efficiency is very high

A triple-GEM telescope for the TOTEM experiment

The TOTEM experiment at LHC has chosen the triple Gas Electron Multiplier (GEM) technology for its T2 telescope which will provide charged track reconstruction in the rapidity range 5.3<|eta|<6.5 and a fully inclusive trigger for diffractive events. GEMs are gas-filled detectors that have the advantageous decoupling of the charge amplification structure from the charge collection and readout structure. Furthermore, they combine good spatial resolution with very high rate capability and a good resistance to radiation. Results from a detailed T2 GEM simulation and from laboratory tests on a final design detector performed at CERN are presented.Comment: To appear in the proceedings of 10th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD06), Siena, Italy, October 1-5 200

Production of the front-end boards of the LHCb muon system

This note describes the production of the front end boards CARDIAC, for the 1368 MWPC, and CARDIAC-GEM, for the 12 triple-GEM chambers, of the LHCb muon system. The PCB structure and component layout and the production issues, such as component soldering, quality assurance at the company and delivery rates, are described. The performance of these boards will be the subject of a future publication

Study of T-odd Quark Fragmentation Function in Z0→2Z^0\to 2-jet Decay

The first probe of the correlation of the T-odd one-particle fragmentation function responsible for the left--right asymmetry of fragmentation of a transversely polarized quark and an antiquark is done by using the 1991-95 DELPHI data for $Z\to 2$ jet decay. Integrated over the fraction of longitudinal and transversal momenta, this correlation is of 2.5 ppm order, which means order of 7% for the analyzing power. This makes us hope to use certain effects in polarized DIS experiments for transversity measurement.Comment: 5 pages, 1 eps figure, latex, sprocl.sty and wrapfig.sty. Talk at 13 Int. Symp. on High Energy Spin Phys., submitted to Pro

Test with cosmic rays of the GEM chambers for the LHCb muon system produced in Cagliari

The inner region of the first LHCb muon station will be equipped with twelve Gas Electron Multiplier chambers. The seven chambers produced in Cagliari were studied for several days each using cosmic rays. We measured the efficiency, timing resolution, and uniformity, cluster-size and out-of-time multiplicity. We find all seven chambers perform well

When gravity meets philosophy again: the Gravitas project

Gravity is, by far, one of the scientific themes that have most piqued the curiosity of scientists and philosophers over the centuries. The history of science tells us that when the creative effort of physicists and philosophers to solve the main puzzles of the understanding of our universe met, a new conceptual revolution has started. However, since Einstein's relativistic theories and the subsequent advent of quantum mechanics, physicists and philosophers have taken different paths, both kidnapped by the intrinsic conceptual and mathematical difficulties inherited by their studies. Is it possible to restore a unitary vision of knowledge, overcoming the scientific-humanistic dichotomy that has established itself over time? The answer is certainly not trivial, but we can start from school to experience a new vision of a unified knowledge. From this need, the Gravitas project has born. Gravitas is a multidisciplinary outreach and educational program devoted to high school students (17-19 years old) that mixes contemporary physics and the philosophy of science. Coordinated by the Cagliari Section of the National Institute of Nuclear Physics, in Italy, Gravitas has started on December 2021 with an unconventional online format: two researchers coming from different fields of research meet a moderator and informally discuss about gravity and related phenomena. The public can chat and indirectly interact with them during the YouTube live. The project involved about 250 students from 16 high schools in Sardinia, Italy. Students should also create posts thought for social media whose content is based on the seminars they attended during the project. We present the project and discuss its possible outcomings concerning the introduction of a multidisciplinary approach in teaching physics, philosophy, and the history of contemporary physics in high schools.Comment: To appear in Proceedings of ICHEP 2022 Conference, 6 pages, 8 figures. An extended version of the abstract appears in the pape

Neural correlates of transitive and intransitive action imitation:an investigation using voxel-based morphometry

AbstractThe ability to reproduce visually presented actions has been studied through neuropsychological observations of patients with ideomotor apraxia. These studies include attempts to understand the neural basis of action reproduction based on lesion–symptom mapping in different patient groups. While there is a convergence of evidence that areas in the parietal and frontal lobes within the left hemisphere are involved in the imitation of a variety of actions, questions remain about whether the results generalize beyond the imitation of tool use and whether the presence of a strong grasp component of the action is critical. Here we used voxel-based lesion–symptom mapping to assess the neural substrates of imitating meaningful (familiar, MF) and meaningless (unfamiliar, ML) tool-related (transitive) and non-tool related (intransitive) actions. The analysis showed that the left parietal cortex was involved in the imitation of transitive gestures, regardless of whether they were meaningful or not. In addition there was poor reproduction of meaningless actions (both transitive and intransitive) following damage of the right frontal cortex. These findings suggest a role of right frontal regions in processing of unfamiliar actions

A new method based on noise counting to monitor the frontend electronics of the LHCb muon detector

A new method has been developed to check the correct behaviour of the frontend electronics of the LHCb muon detector. This method is based on the measurement of the electronic noise rate at different thresholds of the frontend discriminator. The method was used to choose the optimal discriminator thresholds. A procedure based on this method was implemented in the detector control system and allowed the detection of a small percentage of frontend channels which had deteriorated. A Monte Carlo simulation has been performed to check the validity of the method