O presente trabalho visa analisar a partir da variação temporal de NDVI, o comportamento da vegetação remanescente das fitofisionomias da Mata Atlântica, na bacia hidrográfica do rio dos Sinos, RS. Para isso utilizou-se uma série temporal de imagens de NDVI do sensor MODIS, englobando o período de 2000 a 2011. A partir dessas imagens foram gerados espectros temporais de NDVI para cada fitofisionomia remanescente presente na bacia. Também empregou-se a Análise por Componentes Principais (ACP) no conjunto de imagens. Como resultados, observou-se através da análise da série temporal de NDVI/MODIS, um padrão sazonal das fitofisionomias da Mata Atlântica. Os espectros temporais revelaram a sazonalidade da vegetação influenciada principalmente pela temperatura, onde no inverno o NDVI atingiu seus menores valores e no verão seus maiores valores. A ACP mostrou-se uma técnica eficiente para analisar a variação espaço-temporal do NDVI na bacia dos Sinos, entretanto, foi ineficiente para distinguir as fitofisionomias presentes na bacia. Assim, conclui-se que, a utilização de séries temporais em estudos ambientais envolvendo o Sensoriamento Remoto é um importante recurso no monitoramento temporal dos recursos naturais e na detecção de possíveis alterações da sua dinâmica. / The present work analyzes, from the temporal variation of NDVI, the behavior of the remaining vegetation phytophysiognomies of the Atlantic Forest, in the basin of the Rio dos Sinos, RS. For this we used a time series of images of the MODIS NDVI, encompassing the period 2000-2011. From these images were generated spectra temporal NDVI for each vegetation type remaining in this basin. Also we used the Principal Component Analysis (PCA) on the set of images. As a result, it was observed by analyzing the time series of NDVI / MODIS a seasonal pattern of vegetation types of the Atlantic. The temporal spectra revealed the seasonality of vegetation influenced primarily by temperature, where in winter the NDVI reached its lowest values, and in summer the higher values. The PCA proved to be an efficient technique to analyze the spatial-temporal variation of NDVI in the basin of the Sinos. However, it was inefficient to distinguish vegetation types present in the basin. Thus, it is concluded that the use of time series in environmental studies involving remote sensing is an important feature in the temporal monitoring of natural resources and the detection of possible changes in their dynamics.

Notre recherche exploratoire, à visée descriptive, explicative et compréhensive consiste à étudier une dimension peu souvent débattue : l’évaluation verbale des élèves par les enseignants au service de la régulation immédiate des apprentissages et des difficultés observées. Nous émettons l’hypothèse qu’en situation d’enseignement-apprentissage, l’enseignant est soumis à des tensions dont il doit s’affranchir pour faire vivre la classe : s’assurer qu’une majorité d’élèves ait construit les connaissances attendues ou favoriser la réalisation des objectifs pédagogiques et didactiques prévus pour la séance. Nous élaborons un modèle sur les pratiques d’évaluation, produit d’interrelations entre les actions d’évaluations formatives et verdictives verbales (AEFV) de l’enseignant, ses représentations de l’évaluation et les contextes périphériques et situationnels. Les données obtenues montrent l’organisation de patterns constitutifs aux interactions entre les AEFV et les réponses (ou les questions) des élèves dans la dynamique temporelle de la séance ; certains inciteraient une régulation du processus d’apprentissage tandis que d’autres contribueraient à l’avancée du processus didactique. Aussi, la recherche de processus organisateurs de ces patterns établit la présence de discernements constitués par les rapports entre le contexte situationnel, les préoccupations de l’enseignant à cibler la construction de contenus disciplinaires précis, à gérer la temporalité pendant la séance et, ses occupations socio culturellement construites. Ces dernières renvoient à la prise en compte les difficultés des élèves et l’achèvement des programmes scolaires de seconde et première scientifique en France. / Our exploratory research, referred to as descriptive, explanatory and comprehensive, consists of exploring a rarely debated area: the verbal evaluation of students by teachers to immediately improve learning and the difficulties observed. We hypothesize that in teaching - learning situations, the teacher is subject to constraining factors that must be overcome in order for the class to move forward: they must ensure that the majority of students build the knowledge expected or meet the educational and didactic objectives planned for the lesson. We will devise a model for the practice of the assessment, using the interrelation of the act of the formative and verbal assessment by the teacher, the representation of their assessment and the situational and peripheral environment. The data obtained, shows the organisation of the constituent patterns of the interactions between the formative and verbal assessment and the answers (or questions) of the students within the determinants of the class; a few encourage a regulation of the process of learning whilst others contribute to the progression of the didactic process. The research into the organisation of these patterns also highlights the presence of discriminating informations (discernements) with regards to the situational context, the concerns of the teacher focused the construction of precise disciplinary content, guided the timing of the class and the socio-cultural aims attained. The latter highlights the understanding of the difficulties of students and the completion of school programmes in years seconde and première scientifique in France.

Made available in DSpace on 2014-12-17T15:03:31Z (GMT). No. of bitstreams: 1 LucianaCM_DISSERT.pdf: 1660460 bytes, checksum: dab339dbdc22796b2b9d04615f1dc630 (MD5) Previous issue date: 2013-04-17 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The potentially toxic cyanobacterial blooms in water bodies are spread across the globe, resulting in the loss of water quality and adverse effects on human health. In arid and semiarid regions, the hydrologic regime characterized by an annual cycle of drought and rain, change the volume and the retention time of the reservoir. Such changes affect the limnological characteristics and causing changes in composition and biomass community of cyanobacteria. The reservoir Cruzeta (Zmax = 8.7 m) is a eutrophic water supply source located in the semiarid tropical (Northeast Brazil). Raised the hypothesis that the hydrological regime of semi-arid tropical is a determining factor in the availability of resources in eutrophic water sources, which influences the composition of dominant species of cyanobacteria. The aim of this study was to analyze the changes in biomass and species composition of cyanobacteria for two annual hydrological cycles and evaluate factors drivers. The study was divided into five distinct periods (dry 2010, rain 2011, dry 2011, rain 2012, dry 2012). The dominant group found in all periods was Cyanobacteria (99% of total biomass), which contributed to the low diversity. The filamentous species Cylindrospermopsis raciborskii was present at both points in almost every study. The colonial species Microcystis panniformis and Sphaerocavum brasiliensis dominated only in periods with lower volumes of water. The diatoms contribute more to the biomass during the period of severe drought. The point near the dam (P1) had phytoplankton biomass larger than the point near the tributary (P2). The dominant species of colonial cyanobacteria lasted until the overflow in P1, and P2 this dominance was until the first rains. The redundancy analysis indicated that physical factors such as light availability and water level were the main factors driving the seasonal succession of phytoplankton. The composition of phytoplankton in spring was alternated by species of filamentous cyanobacteria in conditions of poor stability of the water column, such as Cylindrospermopsis raciborskii, and colonial species under conditions of high stability of the water column, such as Microcystis panniformis and Sphaerocavum brasiliensis. The extremes of torrential rains and severe droughts, governed by the hydrological regime of the semi-arid region led to the availability of resources in the watershed, directing the spatial and temporal dynamics of phytoplankton in the reservoir Cruzeta / As flora??es de cianobact?rias potencialmente t?xicas est?o disseminadas em corpos aqu?ticos por todo o globo, resultando na perda da qualidade da ?gua e efeitos negativos para a sa?de humana. Em regi?es ?ridas e semi?ridas, o regime hidrol?gico, caracterizado por um ciclo anual de seca e chuva, altera o volume e o tempo de reten??o dos reservat?rios. Tais altera??es afetam as caracter?sticas limnol?gicas e, consequentemente, ocassiona mudan?as na composi??o e biomassa da comunidade de cianobact?rias. O reservat?rio Cruzeta (Zmax = 8,7 m) ? um manancial de abastecimento eutr?fico, localizado no semi?rido tropical (Nordeste, Brasil). Levantou-se a hip?tese de que o regime hidrol?gico do semi?rido tropical ? um fator determinante na disponibilidade de recursos em mananciais eutrofizados, o que influencia na composi??o e domin?ncia de esp?cies de cianobact?rias. O objetivo deste trabalho foi analisar as mudan?as na biomassa e na composi??o de esp?cies de cianobact?rias durante dois ciclos hidrol?gicos anuais e avaliar fatores direcionadores. O estudo foi dividido em 5 per?odos distintos (seca 2010, chuva 2011, seca 2011, chuva 2012, seca 2012). O grupo dominante encontrado em todos os per?odos foi de Cianobact?rias (99% da biomassa total), o que contribuiu para a baixa diversidade. A esp?cie filamentosa Cylindrospermopsis raciborskii esteve presente em ambos os pontos em quase todo o estudo. As esp?cies coloniais Microcystis panniformis e Sphaerocavum brasiliensis dominaram somente nos per?odos com menores volumes de ?gua. As diatom?ceas contribu?ram mais com a biomassa durante o per?odo de seca severa. O ponto pr?ximo a barragem (P1) apresentou biomassa fitoplant?nica maior que o ponto pr?ximo ao tribut?rio (P2). A domin?ncia das esp?cies coloniais de cianobact?rias se estendeu at? o extravazamento do reservat?rio no P1. No P2, esta domin?ncia ocorreu at? as primeiras chuvas. A an?lise de redund?ncia indicou que vari?veis f?sicas, tais como disponibilidade de luz e o volume de ?gua, foram os principais fatores de condu??o da sucess?o sazonal do fitopl?ncton. A composi??o do fitopl?ncton no manancial foi alternada por esp?cies de cianobact?rias filamentosas nas condi??es de pouca estabilidade da coluna d??gua, como a Cylindrospermopsis raciborskii, e por esp?cies coloniais nas condi??es de elevada estabilidade da coluna d??gua, como Microcystis panniformis e Sphaerocavum brasiliensis. Os eventos extremos de chuvas torrenciais e secas severas, regidos pelo regime hidrol?gico da regi?o do semi?rido determinaram a disponibilidade de recursos no manancial, direcionando a din?mica temporal e espacial do fitopl?ncton no reservat?rio Cruzeta

O presente trabalho visa analisar a partir da variação temporal de NDVI, o comportamento da vegetação remanescente das fitofisionomias da Mata Atlântica, na bacia hidrográfica do rio dos Sinos, RS. Para isso utilizou-se uma série temporal de imagens de NDVI do sensor MODIS, englobando o período de 2000 a 2011. A partir dessas imagens foram gerados espectros temporais de NDVI para cada fitofisionomia remanescente presente na bacia. Também empregou-se a Análise por Componentes Principais (ACP) no conjunto de imagens. Como resultados, observou-se através da análise da série temporal de NDVI/MODIS, um padrão sazonal das fitofisionomias da Mata Atlântica. Os espectros temporais revelaram a sazonalidade da vegetação influenciada principalmente pela temperatura, onde no inverno o NDVI atingiu seus menores valores e no verão seus maiores valores. A ACP mostrou-se uma técnica eficiente para analisar a variação espaço-temporal do NDVI na bacia dos Sinos, entretanto, foi ineficiente para distinguir as fitofisionomias presentes na bacia. Assim, conclui-se que, a utilização de séries temporais em estudos ambientais envolvendo o Sensoriamento Remoto é um importante recurso no monitoramento temporal dos recursos naturais e na detecção de possíveis alterações da sua dinâmica. / The present work analyzes, from the temporal variation of NDVI, the behavior of the remaining vegetation phytophysiognomies of the Atlantic Forest, in the basin of the Rio dos Sinos, RS. For this we used a time series of images of the MODIS NDVI, encompassing the period 2000-2011. From these images were generated spectra temporal NDVI for each vegetation type remaining in this basin. Also we used the Principal Component Analysis (PCA) on the set of images. As a result, it was observed by analyzing the time series of NDVI / MODIS a seasonal pattern of vegetation types of the Atlantic. The temporal spectra revealed the seasonality of vegetation influenced primarily by temperature, where in winter the NDVI reached its lowest values, and in summer the higher values. The PCA proved to be an efficient technique to analyze the spatial-temporal variation of NDVI in the basin of the Sinos. However, it was inefficient to distinguish vegetation types present in the basin. Thus, it is concluded that the use of time series in environmental studies involving remote sensing is an important feature in the temporal monitoring of natural resources and the detection of possible changes in their dynamics.

O presente trabalho visa analisar a partir da variação temporal de NDVI, o comportamento da vegetação remanescente das fitofisionomias da Mata Atlântica, na bacia hidrográfica do rio dos Sinos, RS. Para isso utilizou-se uma série temporal de imagens de NDVI do sensor MODIS, englobando o período de 2000 a 2011. A partir dessas imagens foram gerados espectros temporais de NDVI para cada fitofisionomia remanescente presente na bacia. Também empregou-se a Análise por Componentes Principais (ACP) no conjunto de imagens. Como resultados, observou-se através da análise da série temporal de NDVI/MODIS, um padrão sazonal das fitofisionomias da Mata Atlântica. Os espectros temporais revelaram a sazonalidade da vegetação influenciada principalmente pela temperatura, onde no inverno o NDVI atingiu seus menores valores e no verão seus maiores valores. A ACP mostrou-se uma técnica eficiente para analisar a variação espaço-temporal do NDVI na bacia dos Sinos, entretanto, foi ineficiente para distinguir as fitofisionomias presentes na bacia. Assim, conclui-se que, a utilização de séries temporais em estudos ambientais envolvendo o Sensoriamento Remoto é um importante recurso no monitoramento temporal dos recursos naturais e na detecção de possíveis alterações da sua dinâmica. / The present work analyzes, from the temporal variation of NDVI, the behavior of the remaining vegetation phytophysiognomies of the Atlantic Forest, in the basin of the Rio dos Sinos, RS. For this we used a time series of images of the MODIS NDVI, encompassing the period 2000-2011. From these images were generated spectra temporal NDVI for each vegetation type remaining in this basin. Also we used the Principal Component Analysis (PCA) on the set of images. As a result, it was observed by analyzing the time series of NDVI / MODIS a seasonal pattern of vegetation types of the Atlantic. The temporal spectra revealed the seasonality of vegetation influenced primarily by temperature, where in winter the NDVI reached its lowest values, and in summer the higher values. The PCA proved to be an efficient technique to analyze the spatial-temporal variation of NDVI in the basin of the Sinos. However, it was inefficient to distinguish vegetation types present in the basin. Thus, it is concluded that the use of time series in environmental studies involving remote sensing is an important feature in the temporal monitoring of natural resources and the detection of possible changes in their dynamics.

Estudos sobre a dinâmica de comunidades florestais que avaliam a interação de fatores bióticos e abióticos num determinado intervalo de tempo, expresso pelas diferenças nos valores de mortalidade, recrutamento e crescimento dos indivíduos amostrados, podem fornecer informações sobre a estrutura, mudanças temporais e espaciais, além de fornecer informações sobre a capacidade de regeneração e a ocorrência de perturbações em determinado local. No entanto, pouco se conhece sobre a dinâmica das comunidades Florestais Paludosas, apesar da crescente preocupação na preservação dessas formações ciliares para garantir a manutenção dos recursos hídricos. O presente trabalho teve por objetivo re-amostrar uma comunidade Florestal Paludosa de maneira a descrever a dinâmica temporal, de curto prazo, que pode estar afetando a composição e estrutura local. De forma complementar, estudos sobre o crescimento de plântulas, sobre a fenologia e germinação das principais espécies dessa comunidade foram realizados de maneira a contribuir para que se chegue a um primeiro modelo de dinâmica para esse tipo de floresta. A Floresta Paludosa estudada está localizada na região centro-oeste do estado de São Paulo, próximo das coordenadas 22º 20S e 49º 01W e possui 2,3 ha. Está encravada entre áreas de Floresta Estacional Semidecídua, Campo úmido e Cerradão, no município de Bauru/SP. Os resultados indicam que a estrutura e composição da floresta estudada pouco se alteraram ao longo dos cinco anos e que a dinâmica desta floresta é lenta quando comparada com outras formações vegetais. A relação da ocorrência de espécies e variáveis ambientais foi pequena indicando que as espécies estudadas que ocorrem nestas florestas estão adaptadas as condições abióticas mesmo com algumas variações. O pico de dispersão das principais espécies dessa floresta foi na estação seca e o pico de germinação foi nos primeiros dois meses após serem semeadas, independente da umidade a que estavam submetidas. A rápida germinação e o estabelecimento das plântulas antes dos meses mais chuvosos aumentam as chances de sobrevivência dessas espécies, pois a maior mortalidade entre indivíduos adultos e jovens acontece na época chuvosa. As espécies típicas de formações permanentemente encharcadas Calophyllum brasiliense, Magnolia ovata, Protium spruceanum, Dendropanax cuneatus e Xylopia emarginata, são espécies responsáveis pela formação do dossel, pela manutenção da fisionomia florestal e pela manutenção da fauna dispersora de algumas Florestas Paludosas. Essas já são características suficientes para classificá-las como estruturadores. Podemos acrescentar a esse grupo as espécies Ardisia ambigua e Geonoma brevispatha que apesar de não estarem incluídas em todas as análises realizadas aqui por serem de sub-bosque e uma palmeira com crescimento muito diferente das demais espécies, são comuns a esta formação. Já as espécies Cedrela odorata, Rapanea gardneriana, Styrax pohlii e Tapirira guianensis foram consideradas espécies complementares. Os dois grupos de espécies devem estar presentes em projetos de restauração dessas florestas. As espécies estruturadoras aparentemente tem maior potencial de reconstrução e manutenção do dossel e conseqüentemente do habitat florestal à longo prazo, dando assim condições ao estabelecimento de outras espécies e formas de vida característicos da Floresta Paludosa. / Studies about forest communities dynamics that evaluate the interaction between biotic and abiotic factors during a specific period, expressed by the differences in mortality, recruitment and growth rates of sampled individuals, may provide information about community structure, spatial and temporal changes, in addition to information about forest regeneration capacity and the occurrence of disturbance. Despite the increasing concern about the preservation of these forest formations, in order to ensure the maintenance of water resources, the dynamic of Swampy Forests communities are not well understood. This research aimed to re-sample a swampy forest community, in order to describe its short-term dynamic, which may be affecting local structure and composition. We also carried out a study of seedling growth, phenology and germination of the main species of the community, in attempt to propose a pioneer dynamic model to this type of forest formation. The studied area is located on mid-west region of São Paulo state (22º 20S e 49º 01W), and it has 2.3 ha. The remnant is surrounded by Tropical Semideciduous Forest, wet grasslands and Cerradão, in Bauru city, São Paulo. The results indicate that forest structure and composition have not suffered much alteration along five years of observations, and also that this forest dynamics can be considered slow, when compared to other forest formations. There is a weak relationship between species occurrence and environmental variables, what indicates that the species occurring in the area are adapted to abiotic conditions, even though there are variations. The highest dispersion rate of the main species occurred during the dry season, and the highest germination rate occurred during the first two months after seeding, despite the humidity the seedlings were submitted to. Seedlings fast germination and establishment before the rainy months increased their chances of surviving, because higher mortality rates among young and adult individuals occur during rainy season. Calophyllum brasiliense, Magnolia ovata, Protium spruceanum, Dendropanax cuneatus and Xylopia emarginata, which are typical species of permanently wet forest formations, are responsible for canopy structuring, forest physiognomy maintenance, and maintenance of dispersal fauna of other swampy forest remnants. These characteristics are enough to classify them as framework species. Ardisia ambigua and Geonoma brevispatha can also be included in this classification, although their different growth rates in relation to the other species studied here, because they are understorey specie and a palm, respectively. For this reason, these species were not included in all the analysis we realized. Cedrela odorata, Rapanea gardneriana, Styrax pohlii and Tapirira guianensis were considered complementary species. The two groups of species should be present in these forest restoration projects. Framework species apparently has greater potential for reconstruction and maintenance of forest canopy, and therefore the long term persistence of forest habitats, what will provide conditions for the establishment of other species and life forms characteristic of swamp forests.

Psychological safety is a key factor for successful teamwork. Psychological safety signifies that individuals who work together share the belief that their team is safe for interpersonal risk taking. Since the 1970s, researchers have emphasized the importance of psychological safety for work teams in order to deal with changes and related feelings of uncertainty due to a competition-oriented and fast-paced labor market. Numerous studies demonstrated the relevance of psychological safety for learning from failures and for the improvement of performance levels in all kinds of work contexts. Most notably, psychological safety was found to be related to patient safety in clinical contexts. Thus, psychological safety is particularly relevant in team settings where customers or patients depend on the team’s performance, as is the case in hospital teams, care teams, flight crews, and other interdisciplinary team settings. Changes are inherent in the nature of psychological safety. Yet, researchers have just begun to investigate how psychological safety forms and develops over time. First findings on the development are inconsistent and previous research lacks an overall theoretical framework on the effects of time and other group-bounded factors that affect the development of psychological safety. This dissertation contributs to previous research by focusing on dynamics of psychological safety and embedding the hypotheses into a more holistic theoretical framework on team development over time. More precisely, this work builds on the model of group faultlines that considers group diversity, and more specifically subgroup emergence, as one important origin of psychological safety dynamic across teams. Accordingly, team faultlines, defined as hypothetical lines that split a team into subgroups based on multiple attributes, have a negative impact on the formation of psychological safety. Furthermore, this work refers to a theoretical approach, which emphasizes the inclusion of time in team research thereby encouraging researchers to take a more dynamic perspective on team processes by studying the changes and subsequent effects on team outcomes. As teams are sensitive to signals of psychological safety from the very beginning of teamwork, this work focused on the relation between trajectories of team psychological safety change and team performance. In Study 1, I referred to the Leader-Member-Exchange theory and examined differences in team members’ perceptions caused by subgroup dynamics. Accordingly, members who belong to the in-group of the leader benefit from more exchange of resources compared to members of an out-group. I tested the relation of subgroup belonging and psychological safety in the presence of high or low task conflict, as conflicts are critical events that impact psychological safety. I found that team members who were close to the leader in terms of demographic similarity were less affected by high task conflict compared to members who were demographically different from the leader. This study thus identified a boundary condition of psychological safety, namely subgroup belonging, as being similar to the leader buffered the negative effects of task conflict on perceptions of interpersonal risk-taking. Regarding the development of team perceptions of psychological safety, first studies indicated that psychological safety either remains relatively stable, or slightly decreases over time. In Study 2, I therefore focused on the development of psychological safety and antecedents of both the formation and changes over time. I tested for the effects of three well-studied deep level diversity attributes, namely values, team ability, and team personality, and for effects of group faultlines on psychological safety. The results showed that psychological safety decreased over time. Furthermore, teams who had a strong attitude toward teamwork and were characterized by a weak faultline started into the project with high initial levels of psychological safety (as compared to teams with low attitude toward teamwork and strong faultlines). Yet, in teams with high task-specific skills, psychological safety decreased (as compared to teams with low skills), whereas in teams with high team conscientiousness, psychological safety increased over time (as compared to teams with low team conscientiousness). This study demonstrated the relevance of considering temporal dynamics of psychological safety in team research. Further studies should investigate which factors, other than time, predict the negative development. Does it reflect a natural phenomenon in teams, or are there other mechanisms that explain this finding more accurately such as cross-subgroup communication? Furthermore, important conditions for the formation and development of psychological safety were identified that could provide starting points for the design of interventions regarding how and when the development of psychological safety should be supported from leaders or team coaches. As a consequence of the previous results, the focus of the third study was put on team trajectories of psychological safety, more precisely, whether changes of psychological safety affected team variables such as team performance. According to team development theories, the first half of a project is decisive as team members lay the foundation for important changes around midpoint. A constructive discussion and evaluation at midpoint again separated high- from low-performing teams. Thus, besides absolute levels, relative changes should affect team performance. The results support this proposition as changes of psychological safety predicted team effectiveness above and beyond absolute levels. Taken together, this work highlights the effects of subgroup dynamics and time for research on psychological safety. This dissertation is a pioneer work as all three studies provide crucial insights on dynamics of psychological safety opening up implications for practitioners and new avenues for future research. / Psychologische Sicherheit ist ein Schlüsselfaktor für erfolgreiche Teamarbeit. Psychologische Sicherheit bedeutet, dass Personen, die zusammenarbeiten, den Glauben teilen, dass das Team sicher ist, um interpersonelle Risiken einzugehen. Seit Mitte der 70er Jahre betonen Forscher die Bedeutung von psychologischer Sicherheit für Arbeitsteams und deren Umgang mit den Veränderungen und der damit verbundenen Unsicherheit verursacht durch einen wettbewerbsorientierten und schnelllebigen Arbeitsmarkt. Zahlreiche Studien zeigen die Relevanz von psychologischer Sicherheit für das Lernen aus Misserfolgen und die Verbesserung der Teamleistung in verschiedenen Arbeitskontexten auf. Ein Befund zeigt, dass psychologische Sicherheit mit der physiologischen Sicherheit von Patienten assoziiert ist. Folglich ist psychologische Sicherheit insbesondere dann von Bedeutung, wenn Patienten oder Klienten von der Leistung eines Teams abhängig sind, wie das bspw. in OP-Teams, Pflegeteams, Flugbesatzung, oder anderen interdisziplinären Settings der Fall ist. Obgleich psychologische Sicherheit auf Gruppenebene konzeptualisiert ist und Veränderungen in der Natur dieses Konstruktes liegen, haben Forscher erst vor Kurzem begonnen zu untersuchen, wie psychologische Sicherheit entsteht und sich im Verlauf der Zusammenarbeit verändert. Jedoch sind die Befunde inkonsistent und der Forschung fehlt ein konzeptuelles Rahmenmodell darüber, wie die Zeit und andere durch die Gruppe bedingte Faktoren die Entwicklung von psychologischer Sicherheit beeinflussen. Diese Dissertation trägt zur vorherigen Forschung bei, indem sie den Fokus auf die Dynamiken psychologischer Sicherheit legt und die Forschungsthesen in ein ganzheitliches theoretisches Rahmenmodell zur Entwicklung von Teams einbettet. Im Einzelnen stützt sich die Arbeit auf das Modell der Gruppenbruchlinien, das Gruppendiversität als eine wichtige Ursache für dynamische Prozesse in Teams aufgrund von Subgruppenbildung ansieht. Demnach haben Gruppenbruchlinien (Faultlines), sogenannte hypothetische Linien, die Teams in homogene Subgruppen anhand multipler Attribute teilen, negative Folgen auf die Entstehung von psychologischer Sicherheit. Weiterhin bezieht sich die Arbeit auf einen theoretischen Ansatz, der den Einbezug der Zeit in den Vordergrund rückt und Forscher ermutigen soll eine dynamischere Perspektive auf Teamprozesse einzunehmen und Veränderungen sowie deren Folgen für Teamarbeit zu studieren. Da Teams von Beginn an und in den frühen Phasen der Zusammenarbeit für Signale psychologischer Sicherheit empfänglich sind, lag der Fokus auf Veränderungen in der psychologischen Sicherheit und dem Zusammenhang zwischen Veränderungen und Teamleistung. In Studie 1 bezog ich mich auf die Leader-Member-Exchange Theorie und untersuchte Unterschiede in der Wahrnehmung von psychologischer Sicherheit von Teammitgliedern aufgrund von Subgruppendynamik. Demnach profitieren In-Group Mitglieder der Führungskraft von einem höheren Austausch von Ressourcen im Vergleich zu Mitgliedern der Out-Group. Ich testete die Beziehung von Subgruppenzugehörigkeit und psychologischer Sicherheit in der Präsenz von hohem vs. niedrigem Aufgabenkonflikt, da Konflikte kritische Ereignisse sind, die sich negativ auf die psychologische Sicherheit auswirken können. Ich fand heraus, dass Teammitglieder, die mit ihrer Führungskraft demographisch ähnlich waren, von den negativen Auswirkungen von Aufgabenkonflikt weniger betroffen waren als Teammitglieder, die sich von der Führungskraft diesbezüglich unterschieden. Diese Studie identifiziert eine Grenzbedingung für psychologische Sicherheit, nämlich die Subgruppenzugehörigkeit, da die demographische Nähe zur Führungskraft den negativen Effekt von Aufgabenkonflikt für die Wahrnehmung von psychologischer Sicherheit pufferte. Hinsichtlich der Entwicklung von psychologischer Sicherheit, legen erste Studien nahe, dass sie sich nicht verändert, bzw. Über die Zeit leicht abnimmt. In Studie 2 untersuchte ich daher die Entwicklung von psychologischer Sicherheit und Antezedenzien für die Entstehung und Veränderungen im Verlauf der Zeit. Ich testete für Effekte von drei gut erforschten tieferliegenden Diversitätsattributen, nämlich Werte, Teamfähigkeit und Teampersönlichkeit. Die Ergebnisse zeigen, dass psychologischer Sicherheit über die Zeit abnahm. Darüber hinaus starteten Teams, die eine positive Einstellung zu Teamarbeit hatten und deren Gruppe von schwachen Faultlines gekennzeichnet war, mit einem hohen Anfangsniveau an psychologischer Sicherheit in die Projektarbeit (im Vergleich zu Teams mit negativer Einstellung zur Teamarbeit und starker Faultline). Allerdings nahm die psychologische Sicherheit in Teams mit hohen aufgabenspezifischen Fähigkeiten (im Vergleich zu niedrigen aufgabenspezifischen Fähigkeiten) über die Zeit ab, wohingegen sie in Gruppen mit hoher Gewissenhaftigkeit (im Vergleich zu niedriger Gewissenhaftigkeit) zunahm. Die Studie zeigt die Relevanz der Berücksichtigung von zeitlichen Dynamiken der psychologischen Sicherheit in der Team Forschung. So kann weiterführend dazu geforscht werden, welche anderen Faktoren als Zeit die negative Entwicklung vorhersagen. Handelt es sich hierbei um eine natürliche Entwicklung in Teams, oder erklären andere Mechanismen wie bspw. Kommunikation über Subgruppen hinweg diesen Befund? Darüber hinaus wurden wichtige Konditionen für die Entstehung und Entwicklung von psychologischer Sicherheit identifiziert, die zur Planung von Inhalten und dem Timing von Teaminterventionen zur Förderung der psychologischen Sicherheit durch Führungskräfte oder Team Coaches genutzt werden können. Als Konsequenz der vorherigen Ergebnisse, lag der Fokus der dritten Studie auf den Teamverläufen von psychologischer Sicherheit, präziser noch, auf den Effekten von Veränderungen psychologischer Sicherheit und deren Auswirkungen auf andere Teamvariablen wie bspw. Teamleistung. Laut Team Entwicklungstheorien ist die erste Hälfte der Projektarbeit entscheidend da Teammitglieder die Fundamente für bedeutende Veränderungen zur Mitte legen. Eine konstruktive Diskussion und Bewertung zur Mitte des Projektes wiederum trennt Hochleistungsteams von Teams mit schwacher Leistung. Daher sollte neben der absoluten Einschätzung von psychologischer Sicherheit auch die relative Veränderung Auswirkungen auf die Teamleistung haben. Die Ergebnisse unterstützen diese Annahme. Wir fanden dass Veränderungen in der psychologischen Sicherheit die Teameffektivität über die Baseline hinaus vorhersagten. Insgesamt hebt diese Arbeit die Effekte von Subgruppendynamiken und Zeit für die Forschung von psychologischer Sicherheit hervor. Diese Dissertation leistete Pionierarbeit indem alle drei Studien entscheidende Einsichten in die Dynamiken von psychologischer Sicherheit bieten und Implikationen für Praktiker beinhalten sowie neue Bereiche für zukünftige Forschung eröffnen.

Nas últimas décadas, testemunhou-se um crescente interesse no estudo de sistemas complexos. Tais sistemas são compostos por pelo menos dois componentes fundamentais: elementos dinâmicos individuais e uma estrutura de organização definindo a forma de interação entre estes. Devido a dinâmica de cada elemento e a complexidade de acoplamento, uma grande variedade de fenômenos espaço-temporais podem ser observados. Esta tese tem como objetivo principal explorar o uso da dinâmica espaço-temporal em redes visando a solução de alguns problemas computacionais. Com relação aos mecanismos dinâmicos, a sincronização entre osciladores acoplados, a caminhada aleatória-determinística e a competição entre elementos na rede foram considerados. Referente à parte estrutural da rede, tanto estruturas regulares baseadas em reticulados quanto redes com estruturas mais gerais, denominadas redes complexas, foram abordadas. Este estudo é concretizado com o desenvolvimento de modelos aplicados a dois domínios específicos. O primeiro refere-se à utilização de redes de osciladores acoplados para construção de modelos de atenção visual. Dentre as principais características desses modelos estão: a seleção baseada em objetos, a utilização da sincronização/ dessincronização entre osciladores neurais como forma de organização perceptual, a competição entre objetos para aquisição da atenção. Além disso, ao comparar com outros modelos de seleção de objetos baseados em redes osciladores, um número maior de atributos visuais é utilizado para definir a saliência dos objetos. O segundo domínio está relacionado ao desenvolvimento de modelos para detecção de comunidades em redes complexas. Os dois modelos desenvolvidos, um baseado em competição de partículas e outro baseado em sincronização de osciladores, apresentam alta precisão de detecção e ao mesmo tempo uma baixa complexidade computacional. Além disso, o modelo baseado em competição de partículas não só oferece uma nova técnica de detecção de comunidades, mas também apresenta uma abordagem alternativa para realização de aprendizado competitivo. Os estudos realizados nesta tese mostram que a abordagem unificada de dinâmica e estrutura é uma ferramenta promissora para resolver diversos problemas computacionais / In the last decades, an increasing interest in complex system study has been witnessed. Such systems have at least two integrated fundamental components: individual dynamical elements and an organizational structure which defines the form of interaction among those elements. Due to the dynamics of each element and the coupling complexity, various spatial-temporal phenomena can be observed. The main objective of this thesis is to explore spatial-temporal dynamics in networks for solving some computational problems. Regarding the dynamical mechanisms, the synchronization among coupled oscillators, deterministic-random walk and competition between dynamical elements are taken into consideration. Referring to the organizational structure, both regular network based on lattice and more general network, called complex networks, are studied. The study of coupled dynamical elements is concretized by developing computational models applied to two specific domains. The first refers to the using of coupled neural oscillators for visual attention. The main features of the developed models in this thesis are: object-based visual selection, realization of visual perceptual organization by using synchronization / desynchronization among neural oscillators, competition among objects to achieve attention. Moreover, in comparison to other object-based selection models, more visual attributes are employed to define salience of objects. The second domain is related to the development of computational models applied to community detection in complex networks. Two developed models, one based on particle competition and another based on synchronization of Integrate-Fire oscillators, present high detection rate and at the same time low computational complexity. Moreover, the model based on particle competition not only offers a new community detection technique, but also presents an alternative way to realize artificial competitive learning. The study realized in this thesis shows that the unified scheme of dynamics and structure is a powerful tool to solve various computational problems

Biological neuronal networks are a key object of study in the field of computational neuroscience, and recent studies have also shown their potential applicability within artificial intelligence and robotics [1]. They come in many shapes and forms, and a well known and widely studied example is the liquid state machine from 2004 [2]. In 2019, a novel and simple connectivity rule was presented with the introduction of the SpreizerNet [3]. The connectivity of the SpreizerNet is governed by a type of gradient noise known as Perlin noise, and as such the connectivity is anisotropic but correlated. The spiking activity produced in the SpreizerNet is possibly functionally relevant, e.g. for motor control or classification of input stimuli. In 2020, it was shown to be useful for motor control [4]. In this Master’s thesis, we inquire if the spiking activity of the SpreizerNet is functionally relevant in the context of stimulus representation. We investigate how input stimulus from the MNIST handwritten digits dataset is represented in the spatio-temporal activity sequences produced by the SpreizerNet, and whether this representation is sufficient for separation. Furthermore, we consider how the parameters governing the local structure of connectivity impacts representation and separation. We find that (1) the SpreizerNet separates input stimulus at the initial stage after stimulus and (2) that separation decreases with time when the activity from dissimilar inputs becomes unified. / Biologiska neurala nätverk är ett centralt studieobjekt inom beräkningsneurovetenskapen, och nyliga studier har även visat deras potentiella applicerbarhet inom artificiell intelligens och robotik [1]. De kan formuleras på många olika sätt, och ett välkänt och vida studerat exempel är liquid state machine från 2004 [2]. 2019 presenterades en ny och enkel kopplingsregel i SpreizerNätverket [3]. Kopplingarna i SpreizerNätverket styrs av en typ av gradientbrus vid namn Perlinbrus, och som sådana är de anisotropiska men korrelerade. Spikdatan som genereras av SpreizerNätverket är möjligtvis betydelsefull för funktion, till exempel för motorisk kontroll eller separation av stimuli. 2020 visade Michaelis m. fl. att spikdatan var relevant för motorisk kontroll [4]. I denna masteruppsats frågar vi oss om spikdatan är funktionellt relevant för stimulusrepresentation. Vi undersöker hur stimulus från MNIST handwritten digits -datasetet representeras i de spatiotemporella aktivitetssekvenserna som genereras i SpreizerNätverket, och huruvida denna representation är tillräcklig för separation.Vidare betraktar vi hur parametrarna som styr den lokala kopplingsstrukturen påverkar representation och separation. Vi visar att (1) SpreizerNätverket separerar stimuli i ett initialt skede efter stimuli och (2) att separationen minskar med tid när aktiviteten från olika stimuli blir enhetlig.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.