Complexity, Emergent Systems and Complex Biological Systems:\ud Complex Systems Theory and Biodynamics. [Edited book by I.C. Baianu, with listed contributors (2011)]

An overview is presented of System dynamics, the study of the behaviour of complex systems, Dynamical system in mathematics Dynamic programming in computer science and control theory, Complex systems biology, Neurodynamics and Psychodynamics.\u

Neural network mechanisms of working memory interference

[eng] Our ability to memorize is at the core of our cognitive abilities. How could we effectively make decisions without considering memories of previous experiences? Broadly, our memories can be divided in two categories: long-term and short-term memories. Sometimes, short-term memory is also called working memory and throughout this thesis I will use both terms interchangeably. As the names suggest, long-term memory is the memory you use when you remember concepts for a long time, such as your name or age, while short-term memory is the system you engage while choosing between different wines at the liquor store. As your attention jumps from one bottle to another, you need to hold in memory characteristics of previous ones to pick your favourite. By the time you pick your favourite bottle, you might remember the prices or grape types of the other bottles, but you are likely to forget all of those details an hour later at home, opening the wine in front of your guests. The overall goal of this thesis is to study the neural mechanisms that underlie working memory interference, as reflected in quantitative, systematic behavioral biases. Ultimately, the goal of each chapter, even when focused exclusively on behavioral experiments, is to nail down plausible neural mechanisms that can produce specific behavioral and neurophysiological findings. To this end, we use the bump-attractor model as our working hypothesis, with which we often contrast the synaptic working memory model. The work performed during this thesis is described here in 3 main chapters, encapsulation 5 broad goals: In Chapter 4.1, we aim at testing behavioral predictions of a bump-attractor (1) network when used to store multiple items. Moreover, we connected two of such networks aiming to model feature-binding through selectivity synchronization (2). In Chapter 4.2, we aim to clarify the mechanisms of working memory interference from previous memories (3), the so-called serial biases. These biases provide an excellent opportunity to contrast activity-based and activity-silent mechanisms because both mechanisms have been proposed to be the underlying cause of those biases. In Chapter 4.3, armed with the same techniques used to seek evidence for activity-silent mechanisms, we test a prediction of the bump-attractor model with short-term plasticity (4). Finally, in light of the results from aim 4 and simple computer simulations, we reinterpret previous studies claiming evidence for activity-silent mechanisms (5)

International Conference on Mathematical Analysis and Applications in Science and Engineering – Book of Extended Abstracts

The present volume on Mathematical Analysis and Applications in Science and Engineering - Book of Extended Abstracts of the ICMASC’2022 collects the extended abstracts of the talks presented at the International Conference on Mathematical Analysis and Applications in Science and Engineering – ICMA2SC'22 that took place at the beautiful city of Porto, Portugal, in June 27th-June 29th 2022 (3 days). Its aim was to bring together researchers in every discipline of applied mathematics, science, engineering, industry, and technology, to discuss the development of new mathematical models, theories, and applications that contribute to the advancement of scientific knowledge and practice. Authors proposed research in topics including partial and ordinary differential equations, integer and fractional order equations, linear algebra, numerical analysis, operations research, discrete mathematics, optimization, control, probability, computational mathematics, amongst others. The conference was designed to maximize the involvement of all participants and will present the state-of- the-art research and the latest achievements.info:eu-repo/semantics/publishedVersio

Aspects of the regulation of food intake in the dab, Limanda limanda (L.).

The regulation of food-intake in Limanda limanda was investigated, including (a) the role of the stomach as a limiting factor in fish food intake, (b) the qualities of a diet dab respond to and (c) the dynamics of food intake. Fish fed on squid (4.0 U. g'', 76.2% moisture) ate similar daily rations whether fed three times daily or once per day; when fed every three days they were unable to maintain this intake. Fish fed on pellets (18.8 kJ. g'', 8% moisture) could maintain their average daily food intake for all meal intervals tested. After a satiation meal, food intake broadly increased with deprivation time for at least 96 hours with no clear indication that stomach volume was limiting. However, when the data was re-examined using a return map (where meal m is plotted against meal m-1) there was evidence that feeding was restricted by stomach fullness as the interval between meals exceeded 25 hours. Surprisingly such limitation did not occur at higher feeding frequencies. Three models of food intake were used to simulate food-intake data, in which the role of the stomach as a constraining factor was varied: 1) Food intake was assumed always to be completely limited by stomach volume. 2) Food-intake was assumed always to be driven by a systemic need 3) Food intake was assumed to be chiefly limited by a systemic need, but when this was high, stomach volume would constrain intake. Comparisons of experimental results with these models suggest that when fish are fed frequently, or on a high-energy diet, the stomach volume is probably not limiting, whereas for a low-energy diet, fed infrequently, stomach volume was limiting when systemic need was high. Dab adapted their food intake to diets of different water content (and therefore energy density). They also adapted the distensibility of their stomachs in response to the increased volume eaten; fish fed on pellets having less distensible stomachs than those fed on squid. Thus it is unlikely that stomach volume can limit food intake in the long term, unless food quality and/or meal timing is variable and the fish cannot adapt their stomachs to the diet/feeding frequency. Methodological trials proved that that observed stomach VI volume is a function of the measurement technique, as well as the diet history of the fish, and experiments examining stomach volume should take this into consideration. The question of what aspect of a diet L. limanda adapt to was examined by testing different models using path analysis, a method of inferential modelling of causal relationships, in an attempt to explain how food-intake is regulated. Dab were found to be adapting to both the energy content of the diet and to the individual nutrients. The dynamics driving food intake in groups of dab were investigated using non-linear time series analyses. These proved to be low-dimensional, significantly non-linear, deterministic systems. The data also suggests that such systems are either capable of occasional chaotic behaviour, or are on the edge of chaos i. e. complex dynamical systems. Thus food intake is under the direct control of few (two or three) variables, through which the many known factors that influence food intake must act. Comparisons were made with individuals and groups of Oncorhynchus mykiss, with a brief look at Merlangius merlangus and Dicentrarchus labrax. These results were similar to the dab, and so this dynamical behaviour may be a feature of teleost fish in general. Importantly the fact that individual trout had similar feeding behaviour to groups indicate that the findings were not a function of hierarchical dynamics. The significance of this finding should be that appetite control with these properties allows rapid adjustment of fish according to changes in diet quality