Methods for the atomistic simulation of ultrasmall semiconductor devices

As the feature sizes in VLSI technology shrink to less than 100 nm the effects due to the quantisation of electronic charge begin to emerge. There are a small number of carriers and impurities and the statistical variation in their number have significant effects on the threshold characteristics of the devices that hamper their large scale integration into future ULSI.The complex potential landscape arising from the Coulomb force, with its sharp localised peaks and troughs, faces problems due to band limiting in meshes and places heavy burdens on the integration techniques. A computationally efficient solution to the problem of band-limiting is presented and is shown to provide an accurate description of the electrostatics. This work also introduces a highly efficient and numerically stable multigrid solver, for Poisson's equation, that can cope with the complex potential distributions on large meshes.The study of ionised impurity scattering is used to validate these molecular dynamics simulations. Results have shown that the Brownian method - despite precluding the use of adaptive integration schemes - gives a good approximation to the standard results and has the advantage of smoothing away errors that can build up during the integration of motion and drives the system towards thermal equilibrium.The greatest hurdle to be cleared before these three-dimensional simulations can be practicable is the sheer computational effort that is required. The implementation of the problem on parallel architectures has been explored and discussed.The methods developed in this work are demonstrated through the simulation of an 80 nm dual-gate MESFET. The results were verified by comparing them with those from a commercial drift-diffusion simulator.The threshold behaviour of devices has been investigated through the study of the formation of conduction channels in blocks. The percolation threshold gives the point when conductive paths form across the gate barrier. The results from the FET simulation were found to be in agreement with the earlier studies on the blocks

Frontiers in psychodynamic neuroscience

he term psychodynamics was introduced in 1874 by Ernst von Brücke, the renowned German physiologist and Freud’s research supervisor at the University of Vienna. Together with Helmholtz and others, Brücke proposed that all living organisms are energy systems, regulated by the same thermodynamic laws. Since Freud was a student of Brücke and a deep admirer of Helmholtz, he adopted this view, thus laying the foundations for his metapsychology. The discovery of the Default Network and the birth of Neuropsychoanalysis, twenty years ago, facilitated a deep return to this classical conception of the brain as an energy system, and therefore a return to Freud's early ambition to establish psychology as natural science. Our current investigations of neural networks and applications of the Free Energy Principle are equally ‘psychodynamic’ in Brücke’s original sense of the term. Some branches of contemporary neuroscience still eschew subjective data and therefore exclude the brain’s most remarkable property – its selfhood – from the field, and many neuroscientists remain skeptical about psychoanalytic methods, theories, and concepts. Likewise, some psychoanalysts continue to reject any consideration of the structure and functions of the brain from their conceptualization of the mind in health and disease. Both cases seem to perpetuate a Cartesian attitude in which the mind is linked to the brain in some equivocal relationship and an attitude that detaches the brain from the body -- rather than considering it an integral part of the complex and dynamic living organism as a whole. Evidence from psychodynamic neuroscience suggests that Freudian constructs can now be realized neurobiologically. For example, Freud’s notion of primary and secondary processes is consistent with the hierarchical organization of self-organized cortical and subcortical systems, and his description of the ego is consistent with the functions of the Default Network and its reciprocal exchanges with subordinate brain systems. Moreover, thanks to new methods of measuring brain entropy, we can now operationalize the primary and secondary processes and therefore test predictions arising from these Freudian constructs. All of this makes it possible to deepen the dialogue between neuroscience and psychoanalysis, in ways and to a degree that was unimaginable in Freud's time, and even compared to twenty years ago. Many psychoanalytical hypotheses are now well integrated with contemporary neuroscience. Other Freudian and post-Freudian hypotheses about the structure and function of the mind seem ripe for the detailed and sophisticated development that modern psychodynamic neuroscience can offer. This Research Topic aims to provide comprehensive coverage of the latest advances in psychodynamic neuroscience and neuropsychoanalysis. Potential authors are invited to submit papers (original research, case reports, review articles, commentaries) that deploy, review, compare or develop the methods and theories of psychodynamic neuroscience and neuropsychoanalysis. Potential authors include researchers, psychoanalysts, and neuroscientists

The Development and Evaluation of a new Experimental Model of an Active Placebo to Investigate how the Experience of Side Effects Influences the Placebo Effects

Most conventional placebos have no perceptible features and therefore are not likely to mimic a real medication in a RCT or clinical practice. This means that using conventional placebos to understand the placebo effect might not accurately reflect the conditions under which placebo effects occur. This project sought to extend the research on active placebos by developing and evaluating a new experimental model of an active placebo to investigate how perceptible features of a placebo influences its effect. A systematic review and meta-analysis showed that adverse event rates differed statistically significantly between placebo groups of RCTs and that the adverse events experienced in the placebo groups statistically significantly correlated with the adverse events reported by the corresponding medications group. Study 1 demonstrated that the new active placebo model successfully elicited the target side, while being mostly well tolerated. Study 2 showed that most participants receiving a conventional placebo correctly guessed that they had been allocated to the placebo group, while active placebo participants were split evenly between indicating having received a placebo and active medication, suggesting differential blinding as a result of the active placebo. Results from Study 3 indicated no statistically significant effect of message framing on sleep following active placebo administration, nor an overall placebo effect. The findings from this thesis indicated no statistically significant placebo effect on sleep for either conventional or active placebo. Interestingly, however, the results indicate that active placebos can facilitate the maintenance of participant blinding in RCTs and that in such contexts, a lack of side effects might have diminished the placebo response. As such, the active placebo model developed here shed light on how side effects may influence outcomes in RCTs and could help inform the development of techniques to improve blinding in practice

Emotions in Eating Disorders: The Interplay of Emotion Regulation and Inhibitory Control in Appetite and Eating Behaviour

[eng] OBJECTIVES: The main goals of this thesis were to examine the link between the regulation of emotions and disordered eating to obtain insights into the processes underlying ED psychopathology. More specifically, this work aimed to expand upon previous knowledge on emotion regulation in ED patients and upon the effects of these difficulties on eating patterns and craving. An additional aim was to advance the research regarding addiction-like eating and to contribute to the discussion about the validity and usefulness of the FA concept. RESULTS: Study 1: A systematic review of a total of 39 studies showed alterations in emotional facial expression across different mental disorders (obsessive-compulsive disorder, depression, bipolar disorder, borderline personality disorder, AN, BN, autism spectrum disorder, and disruptive behaviour disorder). A meta-analysis showed decreased facial expressivity in response to positive and negative stimuli in patients with AN, with a higher summary effect size for positive (d=1.01) than for negative (d=.58) stimuli. Study 2: ED patients had higher values than HC in the total score and in all subscales of difficulties in emotion regulation. Results furthermore showed that difficulties in emotion regulation mediate the influence of harm avoidance and self-directedness on ED severity. While for self-directedness an indirect and a direct effect on ED was found, the effect of harm avoidance was fully explained through the level of difficulties in emotion regulation. Study 3: This study on predictors of FA in ED patients showed that those patients with higher levels of FA are characterized by lower self-directedness, more negative urgency and less perseverance. The probability of receiving an FA “diagnosis” was predicted by higher reward dependence, higher negative urgency and higher premeditation. Negative urgency was the strongest predictor of FA in patients with an ED. Study 4: Results suggest that of the variables included the only independent predictor of FA might be negative urgency. Self-directedness and emotion regulation predicted negative urgency and were highly related to ED symptomatology in general, but not to FA. Study 5: A systematic review of 26 studies on attentional processing of food stimuli as measured through electrophysiological potentials showed high motivated attention towards food pictures compared to neutral pictures in all participants. This review shows that the type of eating pathology and other factors such as the availability of food and the type of stimuli have an influence on the attentional processing of food cues; however, further research is needed for a better understanding of the subject. Study 6: In this study on stimulus-induced chocolate craving patients with binge-eating pathology reported higher craving than controls; both groups experienced a significant increase in craving when exposed to the smell and sight of chocolate. Amplitudes of electrophysiological event-related potentials were higher for chocolate than for neutral pictures. The Late Positive Potential as measure of motivated attention did not differ between groups. Patients compared to HC had lower baseline amplitudes of an electrophysiological potential related to inhibitory control (N2) in neutral trials but showed a higher relative increase in N2 amplitudes related to chocolate pictures. Priming chocolate pictures by chocolate odour compared to neutral odour led to a slightly increased craving response and to an increased activation of inhibitory control resources in binge-eating patients. CONCLUSIONS: Alterations in facial emotional expressivity and self-reported difficulties in emotion regulation point towards emotional problems underlying ED psychopathology. Unregulated affect and decreased facial emotional expressivity might explain difficulties to recognize own and other’s emotions and thus constrain satisfactory social relations. Negative urgency is a form of impulsivity related to negative affect and is shown to be specifically associated to addictive eating patterns in patients with EDs. There is a possible incentive sensitization of food cues, which is seen in that food stimuli lead to more motivated attention than neutral stimuli.[spa

3-я Міжнародна конференція зі сталого майбутнього: екологічні, технологічні, соціальні та економічні аспекти (ICSF 2022) 24-27 травня 2022 року, м. Кривий Ріг, Україна

Матеріали 3-ої Міжнародної конференції зі сталого майбутнього: екологічні, технологічні, соціальні та економічні аспекти (ICSF 2022) 24-27 травня 2022 року, м. Кривий Ріг, Україна.Proceedings of the 3rd International Conference on Sustainable Futures: Environmental, Technological, Social and Economic Matters (ICSF 2022) 24-27 May 2022, Kryvyi Rih, Ukraine