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Yes / Neuronal activity regulates the transcription and translation of the immediate-early gene Arc/Arg3.1, a key mediator of synaptic plasticity. Proteasomedependent degradation of Arc tightly limits its temporal expression, yet the significance of this regulation remains unknown. We disrupted the temporal control of Arc degradation by creating an Arc knockin mouse (ArcKR) where the predominant Arc ubiquitination sites were mutated. ArcKR mice had intact spatial learning but showed specific deficits in selecting an optimal strategy during reversal learning. This cognitive inflexibility was coupled to changes in Arc mRNA and protein expression resulting in a reduced threshold to induce mGluR-LTD and enhanced mGluR-LTD amplitude. These findings show that the abnormal persistence of Arc protein limits the dynamic range of Arc signaling pathways specifically during reversal learning. Our work illuminates how the precise temporal control of activity-dependent molecules, such as Arc, regulates synaptic plasticity and is crucial for cognition. / Open access funded by Biotechnology and Biological Sciences Research Council

Th. univ.--Litt.--Paris 8, 1978. / Bibliogr. p. 701-723.

Cognitive impairments are an increasing health problem worldwide. In the developed countries, the average life expectancy has dramatically increased over the last decades, and with an elderly population more cases of cognitive impairments appear. Age, genetics, and different medical conditions such as diabetes mellitus, and substance use disorders may all contribute to declined cognitive ability. Physiological functions also decrease with increasing age, as does the activity of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis. Interestingly, both GH and IGF-1 are recognized for their neuroprotective effects and cognitive enhancement. The overall aim of this thesis was to investigate the impact of the somatotrophic axis (i.e. GH/IGF-1 axis) in rodents with cognitive deficiencies induced by diabetes or long-term drug exposure. For the first time cognitive impairments were characterized in diabetic mice using a spatial learning and memory task called the Barnes maze (BM). In diabetic mice, impaired learning in the BM was associated with decreased expression of the GH receptor (GHR) in the frontal cortex, a region important for e.g. working memory. Treatment with GH reversed certain cognitive impairments seen in diabetic animals. In rats treated with gamma-hydroxybutyrate (GHB), a significant decrease of Igf1 mRNA expression in the frontal cortex was observed. This observation may explain the impaired cognitive function previously seen following GHB administration. Furthermore, rats exposed to chronic morphine delivered in mini-osmotic pumps displayed memory impairments in the Morris water maze (MWM), an effect that seems to be associated with the composition of the N-methyl-d-aspartate (NMDA) receptor complex in the frontal cortex. In conclusion, the result strengthens the evidence for GH being a cognitive enhancer. Moreover, the result within this thesis identifies the frontal cortex as an important brain region, where gene expression related to the somatotrophic system is affected in rodents with cognitive impairments. The thesis especially emphasizes the importance of the local somatotrophic system in the brain with regard to cognitive function.

There is a consensus today that we have witnessed the end of postmodernism in both fiction and theory. Due to contemporary fiction’s break with postmodernism being recent, little research has been done to outline the parameters of what exactly this break entails and its relationship to theory and current socio-political issues. The aim of this thesis is to attempt to differentiate between postmodernist fiction and contemporary fiction that was produced from the late 90’s up to today, outline its main characteristics and suggest alternative ways theory may be used to critically analyse fiction. We will be looking at how Habermas’s, Agamben’s, Žižek’s and Badiou’s theories, as well as, a reconsideration of some of Derrida’s and Baudrillard’s theories, can help elucidate certain aspects of contemporary fiction and vice versa. Some of the novelists that will be considered in this discussion are Paul Auster, Don DeLillo, Douglas Coupland, J G Ballard, Julian Barnes, Jonathan Coe and Michel Houellebecq due to their close association with postmodernism and its aftermath. The thesis is divided thematically in five chapters. In the first chapter we will be discussing the impact of 9/11 on contemporary fiction in relation to Derrida’s, Habermas’s, Baudrillard’s and Žižek’s responses to the attacks. The second chapter is concerned with notions of reality and its representations in contemporary fiction. It will be discussed how they differ from Baudrillard’s conceptualisation of hyperreality during postmodernity in light of Badiou’s and Žižek’s theory mainly. The realist/antirealist debate will also be addressed. The third chapter is a consideration of notions of subjectivity in both contemporary theory and fiction and how they may be said to differ from playful, schizophrenic representations of the subject during postmodernity. The fourth chapter is concerned with the return of the political in both theory and fiction after the supposed apoliticality of the postmodern novel, which we will also be addressing. The final chapter is an investigation of the re-emergence of the religious in contemporary culture, including the novel, which proves that the death of meta-narratives may not have been that final after all.

Cette thèse décrit quelques développements dans les techniques de calcul des amplitudes de diffusion en théorie supersymétrique de champ de jauge . L'accent est mis sur les relations de récurrence on-shell et sur l'utilisation de méthodes d'unitarité pour des calculs de boucle. En particulier, la récurrence on-shell est liée aux règles BCFW pour calculer les amplitudes de jauge au niveau des arbres. Les combinaisons de techniques de coupe d'unitarité et la récurrence sont utilisées pour calculer les amplitudes de boucle, et finalement, à partir des amplitudes, pour obtenir la fonction de corrélation énergie-énergie en théorie de super-Yang-Mills N = 4 à l'aide de la représentation de Mellin-Barnes. Dans le dernier chapitre, nous tentons de trouver un contour convergent pour les intégrales de Mellin Barnes en multi-dimension obtenu par une certaine approximation d'un contour de phase stationnaire.

The Austin Steam Train Association operates a tourist train on a stretch of track in Texas from Cedar Park to Burnet. The diverse assortment of restored cars, some dating back to the 1920s, is pulled most-recently by a diesel engine, No. 442, as Southern Pacific No. 786, the original steam engine, is in the process of being repaired. The train requires more than $1 million annually to operate and would have folded long ago if not for an all-volunteer crew. ASTA staffs the crew of at least 10-15 people per train 105-110 times per year and has been doing so for more than 20 years. During a ride on the train, passengers see a wide variety of scenery, including some relics with historical significance. Among them are several large chunks of granite which fell of trains shuttling the stone decades ago from Marble Falls to Austin for the construction of the capitol building. Trains also carried granite to Galveston after the infamous hurricane hit. ASTA also provides entertainment inside the train. Themes rides sell out months in advance. Murder mystery trips are always hits but the Wine Flyer is gaining popularity. With a layover in Burnet on the Saturday Hill Country Flyers trips, passengers take time to explore a new city, have lunch and maybe do a little quick shopping. ASTA takes the operation of the train seriously and makes safety a priority. ASTA runs the train with fantastic dedication and perseverance and subsequently, generates a rolling work of history for study by families, first-timers and enthusiasts alike on a weekly basis. / text

The Cell processor is an example of the trade-offs made when designing a mass market power efficient multi-core machine, but the machine-exposing architecture and raw communication mechanisms of Cell are hard to manage for a programmer. Cell's design is simple and causes software complexity to go up in the areas of achieving low threading overhead, good bandwidth efficiency, and load balance. Several attempts have been made to produce efficient and effective programming systems for Cell, but the attempts have been too specialized and thus fall short. We present Jack Rabbit, an efficient thread pool work queue implementation, with load balancing mechanisms and double buffering. Our system incurs low threading overhead, gets good load balance, and achieves bandwidth efficiency. Our system represents a step towards an effective way to program Cell and any similar current or future processors. / text

We give a rather self-contained introduction to the rare pion to dielectron decay which in nontrivial leading order is given by a QED triangle loop. We work within the dispersive framework where the imaginary part of the amplitude is obtained via the Cutkosky rules. We derive these rules in detail. Using the twofold Mellin-Barnes representation for the pion transition form factor, we derive a simple expression for the branching ratio B(π0 <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Crightarrow" /> e+e-) which we then test for various models. In particular a more recent form factor derived from a Lagrangian for light pseudoscalars and vector mesons inspired by effective field theories. Comparison with the KTeV experiment at Fermilab is made and we find that we are more than 3σ below the KTeV experiment for some of the form factors. This is in agreement with other theoretical models, such as the Vector Meson Dominance model and the quark-loop model within the constituent-quark framework. But we also find that we can be in agreement with KTeV if we explore some freedom of the form factor not fixed by the low-energy Lagrangian.

This thesis examines the writing of U.S. Ambassador to the Soviet Union Joseph Davies, Norman Deuel of the United Press, and Joseph Barnes of the New York Herald Tribune over the course of their respective postings in Moscow between 1936-1938. The purpose of this thesis is to look past interpretations of perceived right and wrong reporting on the Soviet Union and instead identify precisely how and why Americans outside the diplomatic corps viewed and perhaps identified with aspects of Stalinist society. Residing in Moscow over an extended period of time, Davies, Barnes, and Deuel were not mere observers. Immersed in Soviet society, Davies and the press correspondents became themselves producers of socialist realist writing as their American affinity for ambitious modernization translated into an idealized view of Stalinist modernization projects, one which viewed present hardships through a socialist realist lens while echoing Soviet enthusiasm for medical and scientific advancements, material plenty, heroics, youth, and territorial exploration. Excluded from the close-knit circle of career diplomats, Davies and the newsmen also came to view the Moscow show trials through the same socialist realist lens, one which presented the desired utopian future through elaborate socialist realist theatre.