Sistemas dinâmicos não lineares em doença mental

Tese de doutoramento, Ciências Cognitivas, Universidade de Lisboa, Faculdades de Ciências, Faculdade de Letras, Faculdade de Medicina e Faculdade de Psicologia, 2016A mente humana é uma estrutura dinâmica complexa e o seu adoecer deverá ser estudado como o são processos em outras estruturas dinâmicas complexas. Os processos de mudança que operam na mente manifestam-se tipicamente por transições qualitativas e súbitas, sensibilidades específicas a certas influências, e também por resiliência perante a adversidade. Todas estas são manifestações de sistemas não lineares. O propósito desta investigação foi entender as mudanças que operam na mente e que conduzem à doença mental, e concretamente à emergência de perturbações do humor. Os indivíduos com perturbações de humor mostram perdas de complexidade da sua variação de humor, ou seja, maior rigidez, regularidade e previsibilidade. A hipótese central desta investigação é que, face à adversidade, os indivíduos resilientes recrutam estratégias de regulação emocional flexíveis e diversas que aumentam a complexidade do seu humor – a resposta de complexidade. Os indivíduos não-resilientes não são tão hábeis nesta resposta porque empregam estratégias rígidas e menos diversas, fazendo emergir perturbações do humor. Procurou-se evidência deste mecanismo tanto em séries temporais do humor reais, como em simulações de um novo modelo dinâmico do humor. Foram recrutados pacientes com perturbações do humor (N=17) e controlos (N=10) que auto-registaram diariamente o seu humor durante uma média de 233 dias, e foram calculadas a complexidade (sample entropy) e a carga de adversidade a partir das séries temporais. Os resultados mostraram que, tanto nos controlos como nos pacientes a complexidade aumentou com a adversidade, mas os pacientes mostraram disrupções substanciais e significativas dessa resposta, com perdas de até 29% da complexidade esperada nos controlos para a mesma carga de adversidade. Foi proposto um novo modelo dinâmico do humor baseado em equações diferenciais não lineares – o modelo SPLIT-CORE. Este modelo implementa mecanismos de regulação emocional como inércia emocional, ruminação depressiva, estratégias ativadoras e clivagem ou alternância entre modos dinâmicos do self. A afinação destes mecanismos permitiu simular diversas características dinâmicas do humor, entre as quais a resposta de complexidade e a sua disrupção em indivíduos que fazem uso rígido de estratégias de regulação emocional. Crucialmente, a alternância de modos dinâmicos do self foi essencial a uma resposta de complexidade saudável, indicando que esta resposta resiliente é o resultado de meta-flexibilidade do self. Esta investigação mostra, no caso concreto das perturbações do humor, como a afinação singular de um mesmo processo humano global não linear pode originar os padrões dinâmicos de sofrimento e incapacidade que compõem as doenças mentais. Isto permitirá dar conta de como as diferenças individuais interagem entre si e com o ambiente, e ser traduzido em monitorização de risco clínico, diagnóstico de mecanismos de doença e intervenções dirigidas e atempadas sobre indivíduos e circunstâncias concretas. Na dinâmica do humor, a resposta de complexidade individual perante a adversidade pode ser promovida pela diversificação de estratégias de regulação emocional. Resiliência requer humor complexo para vidas complicadas.The human mind is a complex dynamical structure and its falling ill should be studied as are processes in other complex dynamical structures. The processes of change that act in the mind typically manifest as sudden and qualitative transitions, specific sensitivities to certain influences, and also as resilience in the face of adversity. All of these are manifestations of nonlinear dynamical systems. The purpose of this research was to understand the changes that act in the mind which lead to mental illness, and specifically to the emergence of mood disorders. Individuals with affective disorders show losses in the complexity of their mood variation, which appears more rigid, regular and predictable. The central hypothesis of this research is that, in the face of adversity, resilient individuals recruit flexible and diverse emotion regulation strategies that increase the complexity of their mood variation – the complexity response. Non-resilient individuals are not as skilled in this response because they employ rigid and less diverse strategies, giving rise to mood disorders. We searched evidence for this mechanism in both real time series of mood and in simulations of a newly developed dynamical model of mood. We recruited patients with mood disorders (N=17) and controls (N=10) who selfrecorded their daily mood over a mean duration of 233 days, and calculated the complexity (sample entropy) and the load of adversity from the time series. Results showed that, in both controls and patients, complexity increased with adversity but patients displayed significant and substantial disruptions in this response, with losses of up to 29% of the expected complexity of controls for the same load of adversity. We proposed a new dynamical model of mood based on nonlinear differential equations – the SPLIT-CORE model. This model implements emotion regulation mechanisms such as emotional inertia, depressive rumination, activating strategies and splitting or alternation of dynamical modes of the self. The tuning of these mechanisms allowed the simulation of several dynamical features of mood, including the complexity response and its disruption in individuals who rigidly use emotion regulation strategies. Crucially, the alternation of dynamical modes of the self was essential for a healthy complexity response, indicative that this resilient response is the outcome of meta-flexibility of the self. This research shows, in the particular case of mood disorders, how the unique tuning of a same global nonlinear human process may give rise to the dynamical patterns of suffering and disability that comprise mental illnesses. This will allow accounting for how individual differences interact with each other and the environment, and be translated into monitoring clinical risk, diagnosing mechanisms of illness and directing timely interventions to specific individuals and circumstances. Concerning the dynamics of mood, an individual’s complexity response in the face of adversity may be promoted through the diversification of emotion regulation strategies. Resilience requires complex mood for complicated lives

Expansão para oeste do peixe-gato-europeu Silurus glanis no rio Douro (Portugal)

The current study reports the first occurrence and the spread of the European catfish Silurus glanis (Family: Siluridae) in the Portuguese section of the Douro River, suggesting a potential expansion of its distribution in Portugal either via westward dispersal across international rivers and/or human-assisted introductions into new reservoirs and drainages. The European catfish has unique features (e.g., opportunistic predator, hunting, and aggregation behaviour) that make it highly suitable for establishing self-sustaining populations in new areas and likely contribute to its invasion success. The species may severely affect native prey communities and modify food web structure and ecosystem functioning. Efficient and sustainable management actions are needed to prevent further introductions in the future.O presente estudo relata a primeira ocorrência do peixe-gato-europeu Silurus glanis (Família: Siluridae) no troço português do rio Douro, sugerindo uma potencial expansão da sua distribuição em Portugal através da dispersão natural da espécie para oeste através deste rio internacional e/ou através de introduções realizadas pelo homem em novas albufeiras. As características particulares do peixe-gato europeu (por exemplo, predador oportunista e comportamento de caça em grupo) aumentam quer o sucesso da sua dispersão quer o estabelecimento de populações auto-sustentáveis em novas massas de água. Esta espécie pode afetar severamente as comunidades de presas nativas e pode modificar a estrutura da teia alimentar, assim como mudar o funcionamento dos ecossistemas. Desta forma são necessárias ações de gestão eficazes para evitar novas introduções desta espécie.FCTinfo:eu-repo/semantics/publishedVersio

Computational Simulation of an Agricultural Robotic Rover for Weed Control and Fallen Fruit Collection—Algorithms for Image Detection and Recognition and Systems Control, Regulation, and Command

The continuous rise in the world’s population has increased the need for food, resulting in a rise of agricultural holdings to ensure the supply of these goods directly to the populations and indirectly to all processing industries in the food business. This situation has led agriculture to reinvent itself and introduce new technics and tools to ensure tighter control of the crops and increase yields in food production. However, the lack of labor coupled with the evolution of weeds resistant to herbicides created a crisis in agricultural food production. However, with the growing evolution in electronics, automation, and robotics, new paths are emerging to solve these problems. A robotic rover was designed to optimize the tasks of weed control and collection of fallen fruits of an orchard. In weed control, a localized spraying system is proposed, therefore reducing the amount of applied herbicides. With fruit collection, it is possible to direct fallen fruits for animal feeding and possible to reduce microbial activity on the next campaign crops, therefore avoiding damage. This study proposes the simulation of this robotic rover on robotic simulation software. It also proposes the replication of a similar environment of an orchard to generate an algorithm that controls the rover on the tasks of localized spraying and fallen fruit collection. Creating and testing these algorithms by using a robotic simulator speed up and ease the evaluation of different scenarios and hypotheses, with the added benefit of being able to test two tasks simultaneously. This method also allows greater freedom and creativity because there are no concerns about hardware damage. It should also be noted that development costs are very low.info:eu-repo/semantics/publishedVersio

Nannochloropsis sp. Biorefinery: Recovery of Soluble Protein by Membrane Ultrafiltration/Diafiltration

This work proposes a way to maximize the potential of a Nannochloropsis sp. biorefinery process, through membrane technology, producing an extract enriched in soluble proteins, free from the insoluble protein fraction, with a low lipid content and eliminating the colored chlorophyll-a. This procedure, following the principles of a circular economy approach, allows for the valorization of a stream from the biorefining of Nannochloropsis sp. that, otherwise, would be considered a residue without commercial value. The process proposed minimizes fouling phenomena at the membrane surface, making it possible to achieve high permeate fluxes, thus reducing the need for membrane cleaning and, therefore, contributing to an extended membrane lifetime. Supernatant obtained after centrifugation of a suspension of ruptured Nannochloropsis sp. cells was processed by ultrafiltration using a membrane with a cut-off of 100 kDa MWCO. Two different operating approaches were evaluated—controlled transmembrane pressure and controlled permeate flux—under concentration and diafiltration modes. Ultrafiltration operated in a diafiltration mode, under controlled permeate flux conditions, led to the highest soluble protein recovery (78%) with the highest constant permeate flux (12 L·m−2·h−1 ) and low membrane fouling.publishersversionpublishe

Short-Term Herbage Intake Rate in Temperate Pastures Grasses Grown in Pure or in Intercropping Stands

Oat and ryegrass pastures grown in intercropping systems are the most common forages used during the fall and winter in subtropical and in some temperate climate regions. Nevertheless, it must be taken into account that the way in which the different species of plants are presented to the animals may lead to consequences for the efficiency of the grazing process (Prache and Damasceno 2006). Moreover, in hetero-geneous environments, animals may reduce intake rate due to a partial preference for a specific species (Gonçalves et al. 2009). Regarding the pasture development stage, it is known that the decrease of the leaf/stem ratio causes the animal to reduce the instantaneous herbage intake rate due to the reduction of the bite depth because of the physical barrier imposed by the stem (Benvenutti et al. 2006; Drescher et al. 2006) and/or the search for a higher food quality, in this case, leaf lamina (Soder et al. 2009). However, the dynamics of changes in temperate sward structures grown in pure stands compared to inter-cropping systems and its consequence in heifers\u27 short-term herbage intake rate (STHIR) are scarce. The objective of this work was to assess the changes in the STHIR in pastures of oat, ryegrass and their intercrop during the growing season. The hypothesis tested was that cattle reduce the STHIR in intercropping pastures compared to pure stands, and as the grazing season progress

Tiller Size/Density Compensation in Temperate Climate Grasses Grown in Monoculture or Intercropping Systems under Rotational Grazing

From the standpoint of tiller population dynamics, it is well known that the size and numbers of tillers in forage grasses are inversely related, where a greater tiller population density (TPD) is associated with smaller tillers and vice versa (Sbrissia et al. 2003; Hernandez-Garay et al. 1999; Matthew et al. 1995). This relationship has traditionally been made with the self-thinning power law described by Yoda et al. (1963), which considers the leaf area index (LAI) of the pasture constant when the slope of the relationship between numbers and size of tillers, on a logarithmic scale, is approximately -3/2 (Matthew et al. 1995). Notably few studies have assessed this relationship in intercropping systems. Moreover, although studies that evaluated intercrops showed relationships that were nearly -3/2 for the individually analysed species (Yu et al. 2008; Nie et al. 1997;White and Harper 1970), Nie et al. (1997) suggested that all plants that occur in the grass field should be used to properly estimate self-thinning in mixed species pastures. Thus, the aim of the present study was to test the main hypothesis that the tiller size/density compensation mechanisms operate in the same way in mixed pastures of oat and Italian ryegrass under rotational grazing and that the plant communities adapt their population to maintain a relatively constant LAI

An integrated recycling approach for GFRP pultrusion wastes: recycling and reuse assessment into new composite materials using Fuzzy Boolean Nets

In this study, efforts were made in order to put forward an integrated recycling approach for the thermoset based glass fibre reinforced polymer (GPRP) rejects derived from the pultrusion manufacturing industry. Both the recycling process and the development of a new cost-effective end-use application for the recyclates were considered. For this purpose, i) among the several available recycling techniques for thermoset based composite materials, the most suitable one for the envisaged application was selected (mechanical recycling); and ii) an experimental work was carried out in order to assess the added-value of the obtained recyclates as aggregates and reinforcement replacements into concrete-polymer composite materials. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified concrete-polymer composites with regard to unmodified materials. In the mix design process of the new GFRP waste based composite material, the recyclate content and size grade, and the effect of the incorporation of an adhesion promoter were considered as material factors and systematically tested between reasonable ranges. The optimization process of the modified formulations was supported by the Fuzzy Boolean Nets methodology, which allowed finding the best balance between material parameters that maximizes both flexural and compressive strengths of final composite. Comparing to related end-use applications of GFRP wastes in cementitious based concrete materials, the proposed solution overcome some of the problems found, namely the possible incompatibilities arisen from alkalis-silica reaction and the decrease in the mechanical properties due to high water-cement ratio required to achieve the desirable workability. Obtained results were very promising towards a global cost-effective waste management solution for GFRP industrial wastes and end-of-life products that will lead to a more sustainable composite materials industry

Optimization of hemp (Cannabis sativa L.) mechanical and physical properties

Natural fibers are an alternative to the traditional synthetic fibers used for industrial applications and as reinforcement of composites material. Compared to synthetic fibers, the advantages of using natural fibers are their renewability, recyclability, low density, availability in large amounts and low cost [1]. Hemp fiber is used in many applications, it is particularly attractive to reinforcement of composites materials [2]. In this context, a mechanical and physical characterization has been made with hemp fibers grew in Bragança and Mirandela, regions from Portugal, in different conditions of nitrogen fertilization, sowing density, extraction method, and grew location. The objective of the study was to assess the effects of these parameters for optimizing the mechanical properties of hemp fibers. Tensile strength and Young's modulus were determined according to ASTM C1557 [3], density tests were made using a water pycnometer. Average value for tensile strength was 565.3 ± 167.0 MPa, average density was 1.65 ± 0.25 g cm-3 and average Young’s modulus was 92.4 ± 7.4 GPa. A statistical analysis of all parameters was made using ANOVA. The influence of all parameters was determined, the most influent parameter was extraction method and the combined effect of sowing density and nitrogen fertilization, with high influence in specific tensile strength and tensile strength, respectively. Optimal parameters for higher tensile strength were obtained for sowing density of 100 Kg ha-1, nitrogen fertilization of 50 Kg ha-1, extracted with water, cultivated in Bragança. Lower density values were obtained for sowing density of 25 Kg ha-1, nitrogen fertilization of 100 Kg ha-1, extracted with water, cultivated in Bragança. Higher Young's Modulus was determined for fibers from Bragança, with sowing density of 50 Kg ha-1, nitrogen fertilization of 50 Kg ha-1 and extracted with water.info:eu-repo/semantics/publishedVersio

Data mining framework for fatty liver disease classification in ultrasound: a hybrid feature extraction paradigm

PURPOSE: Fatty liver disease (FLD) is an increasing prevalent disease that can be reversed if detected early. Ultrasound is the safest and ubiquitous method for identifying FLD. Since expert sonographers are required to accurately interpret the liver ultrasound images, lack of the same will result in interobserver variability. For more objective interpretation, high accuracy, and quick second opinions, computer aided diagnostic (CAD) techniques may be exploited. The purpose of this work is to develop one such CAD technique for accurate classification of normal livers and abnormal livers affected by FLD. METHODS: In this paper, the authors present a CAD technique (called Symtosis) that uses a novel combination of significant features based on the texture, wavelet transform, and higher order spectra of the liver ultrasound images in various supervised learning-based classifiers in order to determine parameters that classify normal and FLD-affected abnormal livers. RESULTS: On evaluating the proposed technique on a database of 58 abnormal and 42 normal liver ultrasound images, the authors were able to achieve a high classification accuracy of 93.3% using the decision tree classifier. CONCLUSIONS: This high accuracy added to the completely automated classification procedure makes the authors' proposed technique highly suitable for clinical deployment and usage