Understanding the action of an autoequivalence on a triangulated category is generally a very difficult problem. If one can find a stability condition for which the autoequivalence is "compatible", one can explicitly write down the action of this autoequivalence. In turn, the now understood autoequivalence can provide ways of extracting geometric information from the stability condition. In this thesis, we elaborate on what it means for an autoequivalence and stability condition to be "compatibile" and derive a sufficiency criterion. / text

<p>Dans ce travail, les préférences alimentaires pour les espèces végétales consommées par les lombriciens peuplant certains îlots des pelouses de l’avenue Roosevelt ont été étudiées. L’analyse des contenus digestifs et des fèces des vers a montré que les plantes identifiées dans les pelouses ne sont pas toutes consommées.<br> Mesurée par l’indice d’Ivlev, la sélectivité des items végétaux est variable en fonction de l’espèce de ver, de la classe d’âge et de la saison. Lorsque les dicotylédones sont en plein développement au printemps et en été, les choix des vers sont surtout manifestés pour les monocotylédones. En automne et en hiver, les monocotylédones prédominent et, les dicotylédones se retrouvant dans la litière, font l’objet de préférences marquées qui induisent des rejets relatifs de monocotylédones. Bien que Lolium perenne soit la plante la plus consommée, Bellis perennis est la dicotylédone la plus appréciée, Trifolium repens et Poa trivialis étant les plantes généralement rejetées.<br> L’indice d’Ivlev n’ayant permis de connaître que les rangs de préférences des différentes espèces végétales, les analyses ont été complétées par des tests du χ² qui ont montré que la consommation des plantes par les vers ne se fait pas au hasard. <p>Les épigés Satchellius mammalis et Lumbricus rubellus sont les espèces qui présentent le taux le plus élevé de matière organique figurée (respectivement 27 % et 26 % [19 % chez les jeunes Lumbricus spp]) dans leurs contenus digestifs. Chez les anéciques Aporrectodea longa et Lumbricus terrestris, ces taux sont très faibles (respectivement 6 % [2 fois plus chez les jeunes vers] et 11 %). Les endogés (Aporrectodea caliginosa, A. icterica et A. rosea) présentent des taux variant respectivement de 21 % [9 % chez les jeunes vers] à 8 % et 11 %. <p>L’axe de la taille des particules consommées n’a pas permis une ségrégation des niches (d’après notre étude, la taille des vers n’affecte pas celle des particules ingérées), mais l’axe de la nature des particules consommées est plus discriminant. Dans la niche tridimensionnelle (taille et nature des particules ingérées, notre étude, et les cycles annuels d’activité [Tiho, 2001]), le seul recouvrement fort qui se maintienne est celui de la niche de L. rubellus sur celle de L. terrestris. Un recouvrement marginal (α = 0,66) est observé, celui de la niche de A. longa sur celle de L. terrestris. Ceci révèle une compétition interspécifique entre ces trois espèces ayant des régimes alimentaires très proches. <p> <p>In this study, preferences for plants consumed by earthworms inhabiting certain islets of the Roosevelt avenue lawns have been studied. Examination of gut contents and faeces showed that not all of the plants identified in the lawns are consumed.<br> Measured by the Ivlev’s electivity index, the selectivity of plants is variable according to the earthworm species, its size class and the season. When the dicotyledons are developing in spring and in summer, the choices of the earthworms are particularly observed for the monocotyledons. In autumn and winter, the monocotyledons are developing and the dicotyledons in the litter are highly chosen, leading the relative reject of the monocotyledons.<br> Although Lolium perenne is the most consumed plant, Bellis perennis is the most appreciated dicotyledon, Trifolium repens and Poa trivialis being generally rejected.<br> As the Ivlev’s index of preference has only permit to know the rank of preference of the different plants, the analysis was completed by the χ² tests which demonstrated that the consumption of plants by earthworms is not done randomly. <p>The epigées Satchellius mammalis and Lumbricus rubellus are the species which present the highest rate of organic matter (respectively 27 % and 26 % [19 % for the immatures Lumbricus spp] in their gut contents.<br> For the anéciques Aporrectodea longa and Lumbricus terrestris, these rates are very low (respectively 6 % [twice more for the immatures worms] and 11 %).<br> The endogées (Aporrectodea caliginosa, Aporrectodea icterica and Aporrectodea rosea) present rates varying respectively from 21 % [9 % for the young worms] to 8 % and 11 %. <p>The axis of the particles size ingested did not permit the niches segregation (in our study, the earthworms size does not affect the size of the particles ingested), but the axis of the nature of the particles ingested is more discriminant. In the three-dimensional niche (size and nature of particles ingested [our study] and the annuals cycles of activity [Tiho, 2001]), the young worms not being considered, only one high overlap is maintained, that of L. rubellus niche on that of L. terrestris. A marginal overlap (α = 0.66) is observed, that of A. longa niche on that of L. terrestris. Having a similar trophic resource (consumption of litter), an interspecific competition must exist between these three species for the access to the food.

The common view of brand choice in consumer marketing is that brands compete against each other within a specified product category. For example, different coffee brands are compared and evaluated by consumers and the most preferred brand is selected. Is this the only adequate way of demonstrating how consumers make brand choices? This thesis challenges the common view on brand choice and brand choice determinants in consumer markets on several accounts. First, brand choice is made in goal-derived categories (e.g., "foods to eat while on a diet"), and research on goal-derived categories and consumption goals suggests that consumers often choose between brands from different product categories. For example, a consumer may choose between brands of coffee, tea, and soft drinks to fulfill a consumption goal. Second, there is the question of complementarity. Are brands always chosen one by one? We argue in this thesis that consumers often choose brand constellations from complementary product categories in goal-derived categories (e.g., hamburgers and soft drinks when on a short lunch break). The thesis consists of four articles based on empirical studies. The articles cover single-brand choice and brand constellation choice in goal-derived categories, and the use of goal-derived categories by marketing practitioners. The general conclusion is that consumers evaluate more aspects than just brand-related ones when they choose brands in goal-derived categories. Product category associations (i.e., how typical a product category is perceived in a goal-derived category) are a more important determinant of brand (constellation) choice than brand associations. Also, in brand constellation choice, complementarity (i.e., perceived fit between brands) is more strongly related to brand choice than attitude towards individual brands. / <p>Diss. Stockholm : Handelshögsk., 2003</p>

Many piano teachers agree that suitable repertoire motivates their students to learn and practice their instrument. Asking students to learn different categories of repertoire might be a good approach for piano teachers to motivate and maintain their students’ musical interests. However, how do teachers evaluate what kinds of repertoire is presented in the teaching material that is available to them? The purpose of this study is to review the pieces found in North-American piano method books in order to provide an inventory of the different categories of repertoire found in each series and to calculate the proportion of piano repertoire belonging in each category. Consequently, this research will allow piano teachers to see more clearly which kinds of repertoire are in a method book and help select the most appropriate method books for their students.

Microfranchising is emerging as a potentially powerful strategy for reaching the enormous markets at the base of the pyramid (BOP). Microfranchising also represents an effective and sustainable way to contribute to poverty alleviation and economic growth. However, we know little about how organizations maneuver contradictory forces as they use this innovative business model to engage the BOP. To address this gap, I offer a longitudinal case study of an emerging microfranchise effort by a successful Mexican agribusiness—one whose ambitions to continue growing were challenged by multinational agrochemicals suppliers. As this project shows, companies and BOP markets can realize mutual benefits from a value co-creation strategy. Specifically, I adopted a dialectical approach to analyze the tensions and competing forces that arose as business managers and local BOP distributors and producers collaborated in this emerging microfranchising venture. As a result, the research offers three contributions. First, it provides a detailed empirical account of how contradictory forces shaped the Mexican agricultural firm’s implementation of microfranchising to engage with BOP farmers. Second, it presents a conceptual synthesis that describes the major contradictory forces a company faces as it implements microfranchising as part of its BOP strategy. Finally, it offers lessons for how business managers can maneuver contradictory forces to co-create value with the BOP through microfranchising.

Genusforskning inkluderar oftast inte maskulinitet, speciellt inte hur det reproduceras i samhället. Utifrån ett socialpsykologiskt perspektiv utgår därför denna studie från den socialisation som dagligen sker mellan media och samhällsstrukturen. Den här studien beskriver den kulturella representationen av män med hjälp av 80 analyserade filmer och 239 analyserade manliga roller från Sverige och Amerika under 1950- och 2010-talet. En kvalitativ- kvantitativ innehållsanalys genomfördes för att kunna placera de analyserade manliga rollerna i redan existerande maskulinitetskategorier. Resultatet visar att maskulinitet inte får tillräckligt med utrymme i dagens samhälle och kan därmed inte alltid kategoriseras in i dessa maskulinitetskategorier. De största förändringarna av män från 1950-talet och 2010-talet är att vikten av familjen har minskat, samt att mannen har blivit mer känslosam. De största skillnaderna mellan den amerikanska och svenska mannen ligger i hur den amerikanska mannen dominerar i arbetslivet samtidigt som han är familjefar, medan den svenska mannen lever ett ungkarlsliv och lägger stort fokus på sina vänner. / The study of Gender does not often explore masculinity, especially with regards to their role in reproduction in society. The social psychology perspective of the daily socialisation that occurs between media and the social structure is therefore the outset of this study. A cultural representation of men has been described from a dataset of 80 analysed films, and 239 analysed male characters from Sweden and America during the 1950s and 2010s. A qualitative- quantitative content analysis was conducted to place the analysed male characters in already existing categories of masculinity. The results showed that masculinity does not have enough space in today’s society. Due to these findings, many men no longer fit the profile into the existing categories of masculinity. The biggest differences between men from the 1950s and 2010s, was a shift in the importance of family life. Over the years, men have developed a more emotional and sensitive side to themselves. When comparing the difference between the American and Swedish man; The American man tended to dominate his work life while being a family father. Whereas, the Swedish man lived a life of a bachelor and devoted a great deal of time to his friends.

This thesis consists of three parts. In the first part we look at Hopf algebras. We classify pointed rank one Hopf algebras over fields of prime characteristic which are generated as algebras by the first term of the coradical filtration. These Hopf algebras were classified by Radford and Krop for fields of characteristic zero. We obtain three types of Hopf algebras presented by generators and relations. The third type is new and has not previously appeared in literature. The second part of this thesis deals with Auslander-Reiten theory of finitedimensional algebras over fields. We consider G-transitive algebras and develop necessary conditions for them to have Auslander-Reiten components with Euclidean tree class. Thereby a result in [F3, 4.6] is corrected and generalized. We apply these results to G-transitive blocks of the universal enveloping algebras of restricted p-Lie algebras. Finally we deduce a condition for a smash product of a local basic algebra &Lambda; with a commutative semi-simple group algebra to have components with Euclidean tree class, in terms of the components of the Auslander-Reiten quiver of &Lambda;. In the last part we introduce and analyze Auslander-Reiten components for the bounded derived category of a finite-dimensional algebra. We classify derived categories whose Auslander-Reiten quiver has either a finite stable component or a stable component with finite Dynkin tree class or a bounded stable component. Their Auslander-Reiten quiver is determined. We use these results to show that certain algebras are piecewise hereditary. Also a necessary condition for the existence of components of Euclidean tree class is deduced. We determine components that contain shift periodic complexes.

This thesis contains two main results. The first is a comparison formula for the Donaldson-Thomas invariants of two (complex, smooth and projective) Calabi-Yau threefolds related by a flop; the second is a proof of the projective case of the Crepant Resolution Conjecture for Donaldson-Thomas invariants, as stated by Bryan, Cadman and Young. Both results rely on Bridgeland’s category of perverse coherent sheaves, which is the heart of a t-structure in the derived category of the given Calabi-Yau variety. The first formula is a consequence of various identities in an appropriate motivic Hall algebra followed by an implementation of the integration morphism (using the technology of Joyce and Song). Our proof of the crepant resolution conjecture is a quick and elegant application of the first formula in the context of the derived McKay correspondence of Bridgeland, King and Reid. The first chapter is introductory and is followed by two chapters of background material. The last two chapters are devoted to the proofs of the main results.

Quelle est la nature des représentations que se font les gens des catégories apprises? Il est généralement accepté que le type de tâche d’apprentissage a une influence sur la réponse à cette question. Ceci étant dit, la majorité des théories portant sur les processus de catégorisation élaborées durant les dernières décennies a porté presqu’exclusivement sur des tâches de classifications d’exemplaires. Le mémoire présenté ici avait quatre objectifs principaux. Le premier était de vérifier si une tâche d’apprentissage de catégories implicites par classifications mène davantage à l’intégration de dimensions diagnostiques qu’un apprentissage par inférences. Le deuxième était de vérifier si une tâche d’apprentissage de catégories implicites par inférences entraine davantage l’intégration de dimensions typiques qu’un apprentissage par classifications. Le troisième était d’évaluer si un effet de rehaussement du prototype (« prototype enhancement effect ») pouvait être observé dans le cadre d’un apprentissage par inférences. Le quatrième était de clarifier quelle est la mesure de tendance centrale qui présente réellement un effet de rehaussement du prototype : le mode, la médiane ou la moyenne. Suite aux résultats obtenus, les implications pour trois théories portant sur les processus de catégorisation sont discutées. Les trois théories sont celles des prototypes, des exemplaires et des frontières décisionnelles. / What is the nature of the representations people form of the categories they learn? It is generally accepted that the type of learning task has an influence on the answer to that question. That being said, most of the categorization theories elaborated during the last decades have focused almost exclusively on classification-learning tasks. The master thesis presented here had four objectives. First, to verify if a classification-learning task leads to the integration of more diagnostic dimensions than an inference-learning task in the context of implicit categories. Second, to verify if an inference-learning task leads to the integration of more typical dimensions than a classification-learning task, once again in the context of implicit categories. Third, to evaluate if a prototype enhancement effect can be observed in an inference-learning task. Fourth, to clarify which central tendency measure really presents a prototype enhancement effect: the mode, the median or the mean. Given the results obtained, implications for three categorization theories are discussed. The three theories are prototype theory, exemplar theory and decision-bound theory.

Abstract Proof of concept for a continuous environmental sampling methodology that employs common terrestrial arthropods as environmental samplers was tested by analyzing pitfall, malaise and black light captures over a six month period over a replicated urban-suburban-rural gradient in Central Virginia. All arthropods captured at the nine sites were identified and assigned to aquatic, vegetation, or soil groups based on their association with these microhabitats. To offset variability in arthropod life history patterns and species abundance within habitat types, arthropod categories based on presence/absence data over the six month period were constructed to provide for sampling reliability within each microhabitat type. Arthropod categories ranged from single abundant species and families to synthetic groupings based on microhabitat associations (e.g., “soil beetles”), all of which could be easily identified. Mean weekly captures of individuals in each resulting category were compared within and among the nine sites using GLM or ranks analyses. Overall and weekly mean capture rates in the aquatic (two categories), soil (seven categories) and vegetation (11 categories) microhabitats were similar within each habitat type. With the exception of the two aquatic category members (midges and caddisflies), overall, monthly and weekly mean capture rates of all arthropod categories were highest in suburban and lowest in urban habitats. Results demonstrate reliability of the arthropod categories constructed and provide ground truthing for a continuously deployable and user-friendly arthropod-based system for monitoring environmental agents.