The bloodstream form of Trypanosoma brucei differentiates into the stumpy form in the mammalian bloodstream, completing differentiation into the procyclic form on uptake by the tsetse fly. The underlying genetic events occurring during this differentiation process in pleomorphic cell lines were investigated through whole-genome microarray studies of key time points during differentiation from stumpy form cells to the procyclic form found in the insect midgut. The microarray was extensively validated and bioinformatic experiments conducted to detect motifs over represented in stumpy form or slender form cells. A positional-dependent motif was identified that was over represented in stumpy form cells, possibly representing a regulatory domain. The transcripts found to be enriched in stumpy form cells included a chloride channel, although RNAi directed against this gene showed no phenotype, suggesting the protein is redundant, as three other homologous proteins exist in the genome and showed similar mRNA profiles on the microarray. Stumpy form cells are G0 arrested and two proteins implicated in G0/G1 regulation in other organisms, Target of Rapamycin (Tor) and Cdh1, were investigated in T. brucei to determine whether these proteins were involved in differentiation. The result of depletion of either protein was rapid cell death in bloodstream form cells, although treatment with the drug rapamycin did not have any effect on the cells in contrast to other eukaryotes where this drug causes G1 arrest. A method for synchronisation of bloodstream form cells was also designed using a supravital dye and flow cytometry to allow investigation into cell cycle-dependent processes. This method was particularly suitable for harvesting populations enriched in G0/G1 stage cells, however differentiation of the isolated G0/G1 and G2/M populations did not show significantly different differentiation kinetics.

Diss.--München, 1956. / Bibliography: p. 11-16.

Konstanz, Univ., Diplomarb., 2004.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: A, page: 4030. Adviser: John Walter Hill. Includes bibliographical references (leaves 965-1003) Available on microfilm from Pro Quest Information and Learning.

Diss.--München, 1956. / Bibliography: p. 11-16.

Les racines des plantes jouent un rôle important dans la croissance et le développement des plantes, et il est bien connu que les interactions mécaniques entre une croissance racinaire et le sol environnant peuvent avoir un impact majeur sur la croissance des racines et par conséquent sur la production de biomasse végétale. Ces interactions mécaniques sont l'un des nombreux facteurs qui peuvent expliquent la variabilité de l'architecture des racines, y compris les facteurs génétiques, environnementaux et l'instabilité du développement. Mais ce facteur a souvent été sous-estimé. Nous supposons que la structure hétérogène du sol à l'échelle des grains, démontrée par la large répartition des forces, peut influencer d'une manière significative sur les trajectoires de croissance des racines. Ce travail de thèse vise à déterminer comment les grains dans les sols granulaires se réorganisent sous l'action de la croissance des racines, et en retour, comment les forces résultantes agissant sur les apex des racines modifient leur développement, y compris la cinématique de leurs trajectoires. Nous avons développé un modèle numérique 2D de la croissance des racines dans un milieu granulaire en utilisant la méthode des éléments discrets (DEM). Le modèle est capable de calculer les forces de contacts grain-grain et racine-grain dans un milieu granulaire. Le système racinaire est modélisé en utilisant des chaînes d'éléments de spheroline connectés. L'orientation de la croissance des racines, à chaque étape de croissance est déterminée par la dynamique de la racine entière sous l'action des forces élastiques internes et des forces de réaction exercées par les grains, ces sont les interactions mécaniques qui contrôlent la croissance numérique dans le modèle.Des études paramétriques ont été réalisées afin (i) d'estimer l'influence de la structure granulaire (distribution de grains de diamètre, la cohésion, la fraction volumique ...) et les propriétés mécaniques des racines (la rigidité à la flexion) sur le signal de force axiale agissant sur la pointe de la racine, et sur les trajectoires et (ii) de définir les lois physiques générales qui peuvent être utilisées en outre pour analyser des données expérimentales. Les courbes de distribution des forces axiales calculées normalisées par leurs moyens au cours d'une période donnée de la croissance, sont caractérisées par une loi de puissance décroissante pour les forces en dessous de la force moyenne, et une décroissance exponentielle pour les forces ci-dessus de la force moyenne, reflétant ainsi la large répartition des forces à l'intérieur d'un matériau granulaire. Une analyse de l'écart-type des déformations locales des trajectoires des racines, résulte deux régimes en fonction la rigidité de la racine. Une première lorsque le sol contrôle les déformations des racines, et une deuxième lorsque la racine est trop rigide, et se déplace plus les grains environnants durant la croissance. / Plant roots play an important role in the growth and development of plants, and it is well known that the mechanical interactions between a growing root and the surrounding soil can have a major impact on root growth and consequently on plant biomass production. These mechanical interactions are one of numerous factors that explain the variability of root architecture, including genetics, environment and developmental instability. But this factor has often been under-estimated. I hypothesize that the heterogeneous structure of soil at the particle scale, demonstrated by the broad distribution of forces, can significantly influence root growth trajectories. This thesis aims at determining how grains in granular soils are reorganized under the action of growing roots, and in return how the resulting forces acting on root tips modify their development, including the kinematics of their trajectories, in order to develop a general biophysical law of root-soil mechanical interactions. I developed a 2D numerical model of root growth in a granular medium using a Discrete Element Model (DEM). The model is able to compute grain-grain and root-grain contact forces within a granular medium. The root system is modelled using chains of connected spheroline elements. The orientation of root growth at every growth step is determined by the dynamics of the whole root under the action of its internal elastic forces and reaction forces exerted by the grains, which are the mechanical interactions that control numerical growth in the model.Parametric studies were carried out in order to (i) estimate the influence of granular structure (grain diameter distribution, cohesion, volume fraction) and root mechanical properties (root bending stiffness) on the axial force signal acting on the root tip, and on the root trajectories and (ii) define general physical laws that can be used further to analyze experimental data. The distribution curves of computed root tip-grain forces normalized by the mean force during a given period of growth were characterized by a decreasing power law for forces below the mean force, and an exponential fall-off for forces above the mean force, thus reflecting the broad distribution of forces inside the granular material. An analysis of the standard deviation of the local deformations of root trajectories resulted in two different regimes with regard root stiffness. In the first regime, soil controlled the root deformation and in the second, the root trajectory was straighter and displaced more significantly the surrounding grains during growth.

This thesis investigated possible effects of explicit and implicit focus on form (FonF) instruction on the acquisition of Spanish future of probability (SFP) by Anglophone and Francophone students at a Canadian bilingual university. We also analyzed a possible L1 transfer from French to L2 Spanish in the acquisition of SFP, due to the typological similarity of this linguistic feature in the two languages. Twenty seven B1/B2 Spanish level students including L1 English and L1 French learners of L2 Spanish were divided into three groups according to the instruction type: explicit focus on form instruction group, implicit focus on form instruction group and control group, which received no additional instruction. All the participants were tested before the lesson (pretest), immediately after (posttest) and four weeks later (delayed posttest). The battery of tests included Untimed Grammaticality Judgment (UGJT), Written Production (WPT) and Oral Production (OPT) tasks. They aimed to test our four hypotheses which focused on both short-term and long-term effects of the two types of instruction on grammaticality judgment, written and oral production of SFP, respectively. The results demonstrated a positive effect of explicit and implicit FonF instruction on grammaticality judgment, oral and written production of SFP compared to the control group. In particular, both instructional groups distinguished grammatical and ungrammatical uses of SFP with state and activity verbs immediately after the treatment. After four weeks, both groups retained the acquired knowledge equally well. In the implicit FonF group we found an advantage of the L1 French over the L1 English students, possibly due to the similarity of the future tense morphology in Spanish and French, as well as the fact that French uses future morphology for present time probability, although in very limited contexts (a subset of state verbs). The results of the WPT suggest an advantage of the explicit FonF group in both immediate and long-term results and showed no difference between the L1s in either of the instructional groups. We also noticed an overgeneralization of the use of SFP with telic verbs in both instructional groups after the treatment, which is considered ungrammatical. Therefore, our participants did not distinguish the written use of telic and atelic verbs in epistemic conditions after the two types of treatment provided. The OPT results demonstrated that similarly to the previous two tasks both experimental groups performed better than the Control group. However, there was no significant difference between the two instructional groups. L1 had no significant effect on the oral production of SFP either. Similarly to the WPT, we found an overgeneralization of the use of SFP in telic verb conditions. Overall, Anglophone and Francophone students appear to have similar opportunities for successful acquisition of SFP and both explicit and implicit FonF instruction, activities and feedback may lead to positive results in the acquisition of SFP. To conclude this thesis, we discuss some challenges of this study and possible directions of future research.

The block building, Lego construction, pen drawing, and painting of four preschool children were analyzed in terms of the construction of form diversity and new form production. Social descriptive reinforcement, contingent on the production of any form not previously constructed within the current session and overt modeling of forms never seen produced during the study, increased form diversity scores per session and new form production (forms never seen before in the child's total prior sequence of blockbuilding sessions). The results indicated that after training, form diversity scores generalized to topographically similar and dissimilar media of expression. New form production generalized to topographically similar and dissimilar media in the majority of the children.

published_or_final_version / abstract / Psychology / Doctoral / Doctor of Philosophy

<p>Detta examensarbete utreder hur information kan anpassas textuellt och formges efter en specifik målgrupp. Informationen behandlar explosiva och energetiska material, var de används och av vilka, och hur hanteringen sker säkert. Arbetsprocessen har innefattat metoder för textanalys, fokusgrupp och jämställt språk och har lett fram till ett designförslag. De texter som har analyserats har dels varit tagna från examensarbetets samarbetspartner, KCEM, och dels tagna från andra branscher som genom målgruppsanpassat material informerar om sina möjligheter. En fokusgrupp sattes samman av ett representativt urval av målgruppen. Under ett strukturerat gruppmöte fick de kommentera informationsmaterial som riktar sig till dem som homogen grupp. Informationen har anpassats för hela målgruppen genom att tillämpa en metod för jämställt språk. De teorier som sedan använts för att anpassa slutprodukten textuellt och grafiskt är pragmatisk textlingvistik, metadiskurs och visuell metadiskurs. Den pragmatiska textlingvistiken har bidragit med en helhetssyn på språk som ett verktyg för att överföra intentioner och budskap. Metadiskurs och visuell metadiskurs har sedan tillämpats för att överföra teorin till praktiken.</p>