Dissertations / Theses on the topic 'Maze Solving'

The purpose of this report was to examine a method for automatic maze solving by developing a robot that can find a specific target within a maze. On this basis, a Arduino based robot was constructed. The steering mechanism was constructed in a way that supports differential steering which enables zero radius turns which is preferred in narrow spaces. The intersection detection as well as the method for defining which type of intersection occurring was based on three distance sensor mounted in front and on the left and right side of the robot. The target detection was based on a IR sensor. A feedback controller was applied on the left Ultrasonic sensor enabling the robot to keep a reference distance to the wall. The feedback system also enabled the robot to straighten up when taking to big or small turns. The robot was able to both detect and define what kind of intersection occurring as well as detect the specific target. The execution of the correct operation by detected intersection was calculated to 80% - 100% and the target was found 100% out of the test made. The definition of ”correct operation” in this report was when the robot detected a intersection, and executed the operation that was in accordance with the implemented algorithm. The rotational error, that is the quantity of degrees from the desired turn angle, occurring when the robot executed different operations was calculated to 3.5◦ - 9.5◦ . The robot started to oscillate due to angles grater than 19.5◦ when the left distance sensor was facing the wall which made the robot less able to follow a path and straighten up.
Syftet med denna rapport var att undersöka en metod för automatiserad labyrintlösning genom att utveckla en robot som kan finna ett specifikt mål i en labyrint. På dessa grunder konstruerades en arduinobaserad robot. Styrmekanismen konstruerades på sådant sätt att differentialstyrning var möjlig vilket tillät svängar utan svängradie, vilket är att föredra vid trånga utrymmen. Vägkorsningsdetekteringen samt metoden för att bestämma vilken typ av vägkorsning som förekommer baserades på tre distansmätare. Dessa var monterade på robotens front samt på höger och vänster sida. Måldetekteringen var baserad på en IR sensor. Ett system medåterkoppling implementerades på den vänstra distansmätaren för att få roboten att hålla ett referensavstånd till väggen. Detta möjliggjorde även så att vägen kunde följas på ett optimalt sätt samt att roboten kunde rätas upp vid för stora eller för små tagna svängar. Roboten lyckades både detektera samt definiera vilken typ av vägkorsning som uppstod likväl som att detektera det specifika målet. Andelen utförda korrekta operationer vid detekterande av vägkorsning beräknades till 80% - 100% av fallen och målet detekterades 100% av gångerna vid det gjorda testerna. Definitionen av ”korrekt operaton ”i denna rapport var då roboten upptäckte en vägkorsning och utförde den operation som var i enlighet med den implementerade algoritmen. Rotationsfelet, det vill säga antalet grader från den önskade svängvinkeln, som uppstod vid de olika operationerna beräknades till 3.5◦ - 9.5◦ . Roboten började att oscillera vid vinklar större än 19.5◦ då den vänstra distansmätaren var vänd mot väggen vilket gjorde roboten mindre duglig att följa väggen samt att rätas upp.

Evolutionary and swarm based algorithms are subsets of bio-inspired algorithms where    Genetic Algorithm (GA) belongs to the former and Intelligent Water Drops (IWD) to the latter.      In this report we investigate their ability to solve mazes with different complexity.    As performance measures we compare solution quality and success rates.    We find that IWD outperforms GA on mazes of low complexity but results deteriorate quickly as maze complexity increases. GA produces more stable results, better solution quality and a higher success rate for high complexity mazes. Some potential improvements inspired by other works are discussed. We conclude that examining different improvements through stronger subordinate problem-specific heuristics is of interest.
Inom de bio-inspirerade algoritmerna finns bland annat evolutionära och svärmbaserade algoritmer. Genetisk Algoritm (GA) tillhör den förra och Intelligenta Vattendroppar (IWD) den senare. I denna rapport undersöker vi dessa två algoritmers förmåga att lösa labyrinter av olika komplexitet. För att mäta prestandan jämförs lösningskvaliteten samt andelen lösningar där destinationen nås. Vi finner att     IWD utpresterar GA för labyrinter av låg komplexitet men resultaten försämras snabbt när komplexitetgraden stiger. För labyrinter av högre komplexitet producerar GA stabilare resultat med bättre lösningskvalitet och högre andel acceptabla lösningar. Några möjliga förbättringsåtgärder som inspirerats av andras rapporter diskuteras. Sammanfattningsvis fastslår vi att vidare undersökning av olika förbättringar genom starkare underordnade problemspecifika heuristiker är intressant.

This study analyzed and compared four different methods of solving a Rubik’s Cube. Those four methods being the method on Rubik’s official website, the CFOP method, the Roux method and the ZZ method. The factors that were considered were the number of moves each method requires for solving a Rubik’s Cube, how many algorithms they require as well as how concrete or intuitive they are. Our conclusion is that the CFOP, Roux, and ZZ method are fairly equivalent when it comes to move span, but CFOP has the lowest average number of moves used to solve a Rubik’s Cube. CFOP has more concrete algorithms and cases while both Roux and ZZ are more intuitive, ZZ uses fewer types of moves than Roux however. The solution on Rubik’s official website does not compare, at its best it uses as many moves as the others do at their worst. It is however concrete and uses few algorithms for each part.

In this report, genetic algorithms were compared to BFS and DFS for solvingmazes with regards to computational time and solution path length. This wasdone by creating mazes with Wilson's algorithm and running several tests ina controlled environment. The solution path length found by the genetic algorithmwas in general better than the DFS and often almost as good as the onefound by the BFS. The computational time needed by the genetic algorithmhowever was signicantly worse than the time needed by both the DFS and theBFS.
I denna rapport har genetiska algoritmer jamforts med BFS och DFS for attlosa labyrinter med avseende pa berakningstid och losningslangd. Detta gjordesgenom att skapa labyrinter med Wilsons algoritm och kora en stor mangd testeri en kontrollerad miljo. Losningslangderna som den genetiska algoritmen fannvar i allmanhet battre an de av DFS och ofta nastan lika bra som de som BFSfann. Den genetiska algoritmens berakningstid var dock betydligt langre an dentid som kravdes for bade DFS och BFS.

Many studies of children's learning in Art education have focused on the young child working in two-dimensional processes. This study examined ways in which emerging-adolescents worked three dimensionally with clay. The purpose of the study was to discover whether the introduction of adult models of three-dimensional form would affect the way the child perceived and constructed threedimensional form. These models were presented as perceptual frames of reference related to the problem confronting the child. The development of perceptual differentiation skills and perceptual, manipulative and conceptual modes of learning underpin this investigation. Four intact classrooms of 12 year olds were studied and the results were examined by a panel of judges. A rating scale devised by the author was applied to each model. The scale was designed to measure five aspects of three-dimensional form. Results indicated that three-dimensional art works made by adults do affect aspects of the way children approach visual problem solving. Implications for the use of such frames of reference in the art classroom and indications of associated motivational and attitudinal changes are presented in the study.

Background: The study explored the relationship between moral reasoning, distorted cognitions and problem solving in male offenders and non-offenders with intellectual disabilities (IDs). The psychometric properties for an adapted measure of distorted cognitions for people with IDs were explored. The difference in cognitive distortions, moral reasoning and problem solving between offenders and non-offenders were explored. Very few published studies explored these constructs in this way. Methods: A between-groups design and additional correlations were used to explore the hypotheses. Two groups were recruited: ID offenders (n=34) and ID non-offenders (n=38). Both groups completed the Socio-Moral Reflection Measure-Short Form (SRM-SF), How I Think Questionnaire (HIT) and the Social Problem Solving Inventory Short-Form (SPSI-R-SF). Results: The results indicated that offenders with IDs demonstrated Stage 2(3) reasoning when compared to non-offenders with IDs who demonstrated Stage 2 reasoning. The difference in some of the moral reasoning constructs was significant. A modified version of the HIT demonstrated good internal consistency and test-retest reliability. Significant positive relationships were identified between moral reasoning and problem solving, and moral reasoning and cognitive distortions for men with IDs. Conclusions: There was a relationship between moral development, cognitive distortions and problem solving and that these constructs were interdependent. The results supported Gibbs Sociomoral Stages and tentative support for Garrigan and Langdon’s Developmental Social Information Processing Model of Moral Judgement and Behaviour. An adequately powered sample size was used. Social desirability, recruitment and treatment implications were limitations. Further studies should replicate the findings, using a longitudinal design along with the adapted measures.

Objective: Posttraumatic Stress Disorder (PTSD) is highly prevalent in clinical and forensic mental health populations. Understanding the link between childhood maltreatment and the underlying mechanisms that can increase the vulnerability to developing and maintaining PTSD is imperative in clinical conceptualisations and intervention targets. A significant proportion of research is conducted with non mental health populations and there is a paucity of research with forensic populations. The first objective was to review the literature, in clinically related and forensic samples, investigating the association of emotion regulation with childhood maltreatment and Posttraumatic Stress (PTS) symptoms/PTSD. Emotion dysregulation and social problem solving deficits are commonly reported in the forensic population and have been associated with a number of psychopathologies. The empirical study examined the role of emotion regulation and social problem solving skills in the relationship between childhood maltreatment and adulthood trauma symptomatology in a male forensic population. Method: A systematic search of literature investigating the role of emotion regulation in relation to childhood maltreatment and/or PTS symptoms/PTSD was conducted using electronic databases; Medline, PsycINFO, Cinahl, Behavioural and Sciences Collection, EMBASE and PILOTS. Studies that met predetermined inclusion criteria were systematically reviewed. The empirical study employed a cross sectional design to examine the role of emotion regulation and social problem skills in the relationship between childhood maltreatment and adulthood trauma symptomatology. Fifty two male forensic mental health patients completed four self-report questionnaires; Childhood Trauma Questionnaire, Difficulties in Emotion Regulation Scale, Social Problem Solving Inventory-Revised: Short Form and the Post Traumatic Stress Disorder Checklist – Civilian Version. Results: The systematic review indicated strong evidence to suggest links between childhood maltreatment and emotion dysregulation, and emotion dysregulation and PTS symptoms/PTSD within clinically related and forensic samples. Preliminary evidence suggests a mediating role of emotion regulation in the relationship between childhood maltreatment and PTSD. The empirical study found that overall childhood maltreatment, childhood emotional abuse, sexual abuse and emotional neglect were associated with greater emotion dysregulation. Childhood sexual abuse, emotional neglect and physical neglect were associated with poorer social problem solving skills. With the exception of childhood physical abuse, all forms of childhood maltreatment, emotion dysregulation and poor social problem solving were correlated with greater trauma symptomatology. Mediation analysis indicated that both emotion dysregulation and poor social problem solving mediated the relationship between childhood emotional neglect and PTS symptoms in adulthood. Conclusions: The systematic review identified that further research is required within clinical populations to better understand the underlying causal pathways between childhood maltreatment and the development and maintenance of PTS symptoms/PTSD. The empirical study gives further insight into the forensic psychopathology and highlights the relevance of emotion regulation and social problem solving in the treatment of PTS symptoms.

P-aminobenzoic acid (PABA) is a polymorphic compound with two known polymorphs - alpha with a needle morphology and β with a rhombic morphology. It is an enantiotropic compound with a transition temperature at 13.8oC, where alpha is more thermodynamically stable above transition temperature and β is more thermodynamically stable below. At the beginning of this project, crash-cooling crystallisation experiments were conducted to determine the effect of solvent, temperature and supersaturation on the nucleating polymorphs of PABA. Three solvents were tested (water, ethanol and isopropyl alcohol) over a range of supersaturations and temperatures. The results suggested that polymorph appearance of PABA was heavily influenced by kinetics, as opposed to thermodynamics of the system, disagreeing with Ostwald's rule of stages. The project then focussed on the ability of tailor-made additives to select the crystallising polymorph of PABA from supersaturated solutions of PABA in isopropyl alcohol. Crash-cooling crystallisation experiments were performed using two additives: 4-amino-3-nitrobenzoic acid, and 4-amino-3-methoxybenzoic acid. Results showed that alpha PABA crystallised below a critical concentration of either additive, and above that critical concentration, β PABA would crystallise. To determine whether the additives were affecting the nucleation and/or growth kinetics of alpha PABA and β PABA, a series of nucleation and growth experiments were conducted using a Crystal16 multiple stirred reactor and a crystal growth cell respectively. The results showed that both additives greatly reduced the attachment frequency of growth units to alpha PABA nuclei, and inhibited the growth rate of alpha PABA seed crystals. Nucleation data could not be obtained for β PABA, but in terms of crystal growth, both additives did not affect growth rate of β PABA to a noticeable degree. Gravimetric and HPLC experiments were also employed to measure the solubility effects of both additives on PABA in isopropyl alcohol. Results showed that both additives did not appear to affect PABA's solubility to a noticeable degree.

Un extrait hexanique comportementalement actif est obtenu par rincage superficiel de la cuticule des femelles. La composition chimique de cette fraction est analysee par chromatographie et spectrometrie. Les composes a effet aphrodisiaque sont des hydrocarbures a longues chaines (37 carbones) satures et ramifies avec 2 radicaux methyl. Les constituants epicuticulaires des males ne depassent pas 31 atomes de c. Chez les larves des 2 sexes, les composes leges disparaissent en meme temps que se mettent en place les composes plus lourds. La pheromone sexuelle supposee chez les femelles de g. T. Est assez specifique. Cependant la specificite de reponse des males n'est pas etroite

碩士
國立東華大學
電機工程學系
105
Since the artificial intelligence techniques developed, there have been a number of different maze solving algorithms in many publications. In this thesis, experimental results of the selected five maze solving algorithms performed in a line-following maze-solving micromouse robot are illustrated with comparison. The selected five algorithms contain the rules of the left-hand side, right-hand side, forward-first and left, forward-first and right, and left-first and right. All these algorithms are performed in the maze-solving micromouse robot. For practical experiments, an Arduino-based micromouse robot with the selected five maze-solving algorithms were developed. To give comparative discussion, experimental results from the developed micromouse robot are illustrated at last.

碩士
國立臺北科技大學
機電整合研究所
98
Robotic technology is developing quickly in the last few decades. Robots in early generations could only do simple and repeatable works, but now robots need to be smarter. One of many different kind robots is an autonomous mobile robot whose task is making decisions to find its own moving path. A micromouse is a mini, mobile, and autonomous robot which is specifically designed to find a way from a starting point to a destination point in an unknown maze as fast as possible. An efficient algorithm developed for an intelligent robot is highly required to avoid being trapped in the maze and find the shortest path as soon as possible. Herein, an improved maze solving algorithm employing potential value method is proposed in this thesis. Simulation results show that the proposed algorithm is capable of identifying the path by giving different maze configurations and has better performance than the original algorithm from a conference paper based on student’s t-test results. Furthermore, the simulation program can simulate all stages in a micromouse competition, including path finding from the starting cell to the destination cell, from the destination cell to the starting cell, and running back reversely on the shortest path. After testing the algorithms using a simulation program, the algorithms are implemented into a real micromouse robot AIRAT 2, which is a commercial mouse. The evaluation for this implementation is mainly based on the maze solving algorithms to verify the shorter way to the target, while wall sensing, motor control and movement speed are not the major concerns. The evaluation result shows that AIRAT 2 can solve not all types of maze can be solved properly; it is not because a defect in the searching algorithm but the navigation method needs to be improved.

碩士
臺北市立教育大學
課程與教學研究所
94
This study aims to investigate the error patterns that may occur when the second-grade pupils try to solve multiplication problems and the factors leading to these error patterns. The subjects of this study are the second-grade pupils in a primary school in Taipei City and the total of the sample amounts to 384 children, including the thirty-six ones interviewed. The study includes quantitative methods and qualitative analysis of the interview data. Based on the results of the study, the following conclusions are provided: 1.In the overall twenty-seven questions, there are twelve questions in which more than twenty percent of the sampled children made errors. Thus the conclusion is made that many of the sampled second-grade pupils still have difficulty in dealing with multiplication problems. 2.The variation of the children’s performance in solving the multiplication problems shows that the types of the problems have more influences on the second graders’ multiplication errors than that of the samples’ gender. 3.The error patterns in solving multiplication problems are classified as follows: errors in finding proper strategies, errors in calculation, using wrong conceptions in solving multiplication problems, errors in writing answers, failure to make responses and others. 4.The factors leading to the error patterns in solving multiplication problems are: insufficient conceptions of multiplication, confusions between quantifiers and numbers, misunderstanding and miscoding of the problem in context, misunderstanding of the illustrations, misleading by unnecessary information, misleading by the order of the number in questions, lack of basic skills in arithmetic, the influences of previous learning experiences, lack of verification and lack of motives. According to the conclusions of this study, some suggestions are offered as references for the improvement of teaching, the design of the instructional materials and the needs for further studies.

碩士
國立屏東科技大學
食品科學系所
103
Banana Musa spp. (AAA), a member of perennial herb, is the fruit of banana trees. It is one of the most common fruit all over the world due to its high production. According to the literature that the banana has a rich dietary fiber, potassium, magnesium and many other substances beneficial to humans. The banana also increases capacities of immunity, anti-oxidation and anti-cancer, improves cardiovascular health, lowers blood pressure and even affects the treatment of depression. Banana farmers remove the banana flower after banana tree bears fruits in order to control the qualities and nutrition of the banana fruits. Banana flower can be cooked as dishes or made into many other food production; however, tons of banana flower is treated as agricultural waste and dumped in Taiwan every year. In previous studies, banana fruits have showed the capacities of anti-inflammatory and hepatoprotective, but studies related to banana flowers, especially banana buds and bracts, are less than fruits. Therefore, this study was going to analyze total phenol, total anthocyanins, total flavonoids and antioxidant capacity of three solvents extract of banana buds and bracts, which are treated as agricultural wastes while the banana fruits are harvested. Moreover, this study analyzed banana buds and bracts protective ability on injured FL83B liver cells. The results showed that the methanol extraction of banana buds has the maximum contents of total phenol and total flavonoids while the ethanol extraction of banana bracts has the maximum contents of total anthocyanins. Moreover, the methanol extraction of banana buds also has the better antioxidant capacity via DPPH radical scavenging, TEAC and other antioxidant capacity analysis. Toxicity test of mice normal liver cells (FL83B) found that the samples can contribute a better cell growth. And in protection test of the alcohol-induced liver injury, 400μg/mL concentration of methanol extraction of banana buds has significant protection to the mice normal liver cells and their survival rate is up to 92.74%. Besides, 800μg/mL concentration of water extraction of banana buds, methanol extraction of banana bracts and water extraction of banana bracts have obvious results, their rates are up to 89.39%, 91.17% and 85.75% respectively. In conclusion, the banana agricultural waste, such as banana buds and bracts, has considerable potential to be developed as a wonderful antioxidant or a health care food to prevent alcohol injury. Moreover, the new usage of the waste can increase the economic value of agricultural products and also reduce waste.

碩士
國立臺北教育大學
數位科技設計學系(含玩具與遊戲設計碩士班)
107
As teacher in the forefront, one must obtain sharp observations of children's past experience and capabilities to identify the skill sets that are best fit and required. By comparing the differences between the two, one may organize suitable activities, environment and tools to help connect and integrate new and old experiences as to achieve higher levels of learning for the children. Researcher observed that children in the class lacked problem-solving ability, but they were very interested in the operation of board games. Researcher thought about how to help children improve problem-solving ability through board games. It is found that the process of making by children's hands can produce more profound learning effects than simple operation. Through the problems encountered in the process of children's self-control, they can better achieve the goal of problem solving. Therefore, the theme of this research is to use “transportation” as learning guides to explore the process of children's making their own board games that integrate with the intended course learning objectives. One may observe the children's capability in solving problems and the instructors’ growth and reflection during the process. In this qualitative research, 27children from the kindergarten of an elementary school located in New Taipei City would be the targets of this research. For three days in a week and an hour each time, the five-week long course with the theme of the land vehicle theme as the main axis would be used to observe children's performances in each activity and for researchers to make adjustments to the course. Through in-class observations, recordings, course evaluations, notes from assistants, children's work portfolios and interviews, grading and so forth, the overall teaching process would be thoroughly reviewed for its effectiveness. The results show that the initiative of children's experimentation depends on the difficulty of the problem, through which one or two excellent peers can stimulate the experimental spirit of other children; children are more profoundly able to explore and patiently complete what they are interested in or experienced; and children are experiencing the process of curriculum construction with more and more diverse and constructive perspectives. Compared with group teaching, children show more initiative to cooperate with peers in group teaching; through practical operation, children acquire more profound and lasting knowledge; self-made board games strengthen the space of peer discussion, thinking and cooperation.

Doctoral Thesis in Chemical Engineering, submitted to the Faculty of Science and Technology of the University of Coimbra
This project was envisaged to develop new reaction systems for Atom Transfer Radical Polymerization (ATRP). The focus of the work was centred on the use of different solvents, namely “greener” alternatives to the use of toxic solvents. The first study involved the polymerization of methyl acrylate (MA) by Supplemental Activation and Reducing Agent (SARA) ATRP in sulfolane. This system required only very low amounts of soluble copper (catalytic system) to afford the control over the polymerization of MA, methyl methacrylate (MMA) and vinyl chloride (VC). Under the same reaction conditions, similar kinetic data have been obtained with sulfolane and dimethyl sulfoxide (DMSO). However, contrary to DMSO, a commonly used solvent in ATRP, sulfolane also allowed to afford the controlled polymerization of styrene (St). This feature is particularly relevant to access a portfolio of block copolymers using the afore mentioned monomers in a single solvent (Chapter 2). In order to increase the rate of the polymerization, small amounts of water were added to the reaction mixture. In addition, the presence of water allowed to use Na2S2O4 as SARA agent as alternative to copper wire, turning the system “greener” (Chapter 3). Following published reports showing an acceleration effect induced by using ionic liquids in radical-based polymerization, the solvent system DMSO/1-Butyl-3- methylimidazolium hexafluorophosphate ([BMIM]-[PF6]) was studied for polymerization of MA catalyzed by Na2S2O4/ CuBr2 / Me6TREN (Me6TREN: Tris [2- (dimethylamino) ethyl] amine. An unexpected synergistic effect between these two solvents was observed. The results revealed an enormous acceleration of the reaction and also an optimum mixture ratio of DMSO/[BMIM]-[PF6]= 50/50 (v/v) (Chapter 4). A study of SARA ATRP of several monomers using different sulfolane based mixtures ([BMIM]-[PF6], triethylene glycol and water) was carried out at room temperature (Chapter 5). Aiming to replace tetrahydrofuran (THF), it was proposed the use of cyclopentyl methyl ether (CPME)/ethanol/water mixtures as a “greener” solvent mixture for SARA ATRP of MA, glycidyl methacrylate, St and VC (Chapter 6). The work continued with the study of the SARA ATRP using a miniemulsion system. For the first time, butyl acrylate (BA) and St were polymerized in the presence CuBr2/EHA6TREN or BPMODA* complexes mediated by Na2S2O4 as the SARA agent. The obtained polymers had a controlled structure and narrow molecular weight distribution (Ð ≤ 1.2). However, the conversion obtained was always low (~20 %). Different strategies were studied to improve the monomer conversion with no success (Chapter 7). Finally, copolymers prepared by ATRP were applied in the stabilization of superparamagnetic iron oxide nanoparticles (hydrophilic and hydrophobic). Different amphiphilic copolymers of poly(ethylene glycol)-block-poly(vinylpyridine) with different compositions and molecular weights were synthesized and used to prepare hybrid nanoaggregates via "self-assembly" in aqueous medium. Theses structures were achieved via tritation or solvent exchange method (tritation method: 24.7 to 613 nm; solvent exchange method: 17.6 to 35.7 nm) (Chapter 8).
Este projeto foi elaborado para desenvolver novos sistemas de reação para polimerização radicalar por transferência de átomo (ATRP: “Atom Transfer Radical Polymerization”). O foco do trabalho foi centrado no uso de diferentes solventes, nomeadamente alternativas "mais verdes" ao uso de solventes tóxicos. O primeiro estudo envolveu a polimerização de acrilato de metilo (MA) por ATRP na presença de um agente de redução e ativação suplementar (SARA) em sulfolano. Este sistema exigiu apenas quantidades muito baixas de cobre solúvel (sistema catalítico) para permitir o controlo sobre a polimerização de MA, metacrilato de metilo (MMA) e cloreto de vinilo (VC). Sob as mesmas condições de reação, dados cinéticos similares foram obtidos com sulfolano e dimetil sulfóxido (DMSO). No entanto, contrariamente ao DMSO, um solvente vulgarmente utilizado em ATRP, o sulfolano permitiu também a polimerização controlada do estireno (St). Esta característica é particularmente relevante para sintetizar um portfólio de copolímeros de bloco usando os monómeros acima mencionados num único solvente (Capítulo 2). Com o objetivo de aumentar a velocidade da reação de polimerização, foram adicionadas à mistura reacional pequenas quantidades de água. Além disso, a presença de água permitiu usar Na2S2O4 como agente SARA, em alternativa ao fio de cobre e tornar o sistema "mais verde" (Capítulo 3). Na sequência de artigos científicos publicados que mostram um efeito de aceleração induzido pela utilização de líquidos iónicos na polimerização radicalar, o sistema solvente DMSO / hexafluorofosfato de 1-butil-3-metilimidazólio ([BMIM]-[PF6]) foi estudado para polimerização do MA catalisado por Na2S2O4, CuBr2 / Me6TREN (Me6TREN: Tris [2- (dimetilamino) etil] amina. Com este trabalho, observou-se um efeito sinergístico inesperado entre estes dois solventes. Os resultados revelaram uma enorme aceleração da reação e também uma proporção óptima de mistura de DMSO / [BMIM]-[PF6] = 50/50 (v / v) (Capítulo 4). O estudo de SARA ATRP de vários monómeros com diferentes misturas à base de sulfolano ([BMIM]-[PF6], trietileno glicol e água) foi realizado a temperatura ambiente (Capítulo 5). Com o objetivo de substituir o tetrahidrofurano (THF), propôs-se o uso de misturas de éter ciclopentilmetil (CPME) / etanol / água como uma mistura solvente "mais verde" para SARA ATRP do MA, metacrilato de glicidilo (GMA), St e VC (Capítulo 6). O trabalho continuou com o estudo do SARA ATRP usando um sistema de miniemulsão. Pela primeira vez foram polimerizados acrilato de butilo (BA) e St na presença de complexos de CuBr2 / EHA6TREN ou BPMODA* mediados por Na2S2O4 como agente de SARA. Os polímeros obtidos tinham uma estrutura controlada e uma polidispersividade baixa (Ð ≤ 1,2). No entanto, a conversão obtida foi sempre baixa (~ 20%). Foram ainda estudadas diferentes estratégias para melhorar a conversão da polimerização mas sem sucesso (Capítulo 7). Finalmente, copolímeros preparados por ATRP foram aplicados na estabilização de nanopartículas superparamagnéticas de óxido de ferro (hidrofílicas e hidrofóbicas). Foram sintetizados diferentes copolímeros anfifílicos de poli(etileno glicol)-blocopoli( vinilpiridina) com diferentes composições e pesos moleculares e utilizados para preparar nanoagregados híbridos por "self-assembly" em meio aquoso. Essas estruturas foram obtidas por métodos de titulação ou método de troca de solvente (método de titulação: 24,7 a 613 nm, método de troca de solvente: 17,6 a 35,7 nm) (Capítulo 8).

S’approvisionner en nourriture est essentiel à la survie et au succès reproducteur. Lorsque les animaux font face à des changements environnementaux brutaux, ils doivent s’ajuster rapidement à leur nouvel environnement et parfois même innover dans leur façon de s’approvisionner. Des processus comportementaux et cognitifs, tels que l’innovation et l’apprentissage, permettent aux animaux d'intégrer de nouveaux comportements à leur répertoire comportemental afin de s'adapter de façon optimale. Les performances cognitives varient entre les individus d’une même population et bien que des études récentes se soient intéressées aux causes de ce phénomène, de convaincantes évidences sont manquantes afin d’expliquer pourquoi ces variations sont maintenues. Au cours de ce mémoire, les questions des pressions de sélection s'exerçant sur les performances d’alimentation par une tâche motrice nouvelle sont abordées afin de mieux comprendre l'évolution des capacités cognitives au sein d'une population captive de diamants mandarins (Taeniopygia guttata). Nous avons tout d'abord testé si les femelles diamants mandarins modifient leurs préférences d'accouplement après avoir observé la performance d'alimentation par une tâche motrice nouvelle des mâles. Afin de déterminer si les femelles sont capables de discriminer entre les mâles sur la base de leur capacité cognitive, nous avons également évalué les performances d’apprentissage de chacune d’elles. En effet, des études ont suggéré qu’il peut être coûteux, spécialement en terme de temps, de discriminer entre des partenaires potentiels sur cette base. La généralisation d’une préférence pour un mâle performant à d’autres mâles possédant le même phénotype permettrait la réduction de ces coûts. Nous avons donc finalement testé si les femelles diamants mandarins peuvent généraliser leur préférence après avoir observé les performances d’alimentation pour une tâche motrice nouvelle d’un mâle. Nos résultats suggèrent que les femelles diamants mandarins ne peuvent évaluer les capacités cognitives d’un mâle par l’intermédiaire de traits indicateurs. Toutefois, nous avons démontré qu’une observation directe des performances d’alimentation d’un mâle guide le choix d’appariement des femelles. Également, nous avons montré que les femelles peuvent généraliser l’apparence du mâle le plus performant et utiliser cette information lors de l’évaluation de nouveaux mâles. La relation entre les performances cognitives et le choix de partenaire pourraient s’expliquer par exemple par une meilleure exploitation de l’habitat, mais nécessite des études plus approfondies.
Successful foraging is essential for survival and reproductive success. When animals face rapidly change due to climate change or anthropogenic habitat destruction, they are force to quickly adjust their behaviour such as foraging. Innovation and learning, two processes related to cognitive functions, are know to allow animals to incorporate novel behaviours into their behavioural repertoires and thus to facilitate optimal responses to environmental change. Cognitive performance vary between and within individuals and although several studies have rencently addressed the causes, convicing evidences for why inter-individual variations in cognitive performance are maintained in a population are still lacking. During my Masters, I investigated different selective pressures acting on foraging performance on a novel motor task to better understand the evolution of cognitive abilities in a captive population of zebra finch (Taeniopygia guttata). Firstly, we investigated whether female zebra finches modify their mating preferences after having observed the foraging performance of males on a novel motor task. We also assessed each bird’s learning performance in a color associative task in order to check whether females could discriminate between the two males based on their learning performance. Discriminating among mates based on their cognitive ability might be very costly for females, especially in terms of time. Therefore, one way to reduce the cost of assessing mate would be to generalize their preferences to any male with the same phenotype as the most efficient observed individual. We finaly investigated whether female zebra finches can generalize their mating preferences after having observed a male’s foraging performance on a novel motor task. Our findings suggest that female zebra finches would be unable to assess male cognitive ability indirectly via morphological traits. However our results demonstrate that direct observation of the males’ performance on a foraging task can guide female mating preferences. We also demonstrates that female zebra finches can generalize the appearance of the male that is the most efficient at solving a motor task and then use this information to assessing new males. The relationship between cognitive performance and mating preference might be mediated throught habitat exploitation for example, but requires further investigation.

OBJECTIVES: To describe ways of coping in people with mild to moderate AD when faced with situations that are challenging to their memory. METHOD: Twenty-four participants (12 with mild and 12 with moderate AD) were presented with a set of seven tasks that were analogues of everyday situations that tax memory. The participants' responses were videotaped and analysed. RESULTS: Participants' coping responses were grouped into seven categories to best reflect the main strategies. Individuals used a significantly greater frequency of effortful problem solving (self-reliance and reliance on carers) (p < 0.01) than other ways of coping. Positive acknowledgement of memory difficulties was used significantly more than negative acknowledgement and defensive coping (concealment and avoidance) (p < 0.01). CONCLUSION: This study used novel methodology of observation of behavioural responses in analogues of everyday situations. The predominance of effortful problem-solving emphasizes the role of the person with AD as an active agent in the management of memory loss. An emphasis in previous literature on defensive coping and denial is counter-balanced by the finding that participants commonly coped by acknowledging their memory impairment.