Renormalization of cavity field theories

Bibliography: pages 95-97.A major obstacle to calculating Feynman diagrams in field theories, confined to a cavity, has always been the divergent loop diagrams. So far, only the quantum chromodynamic and electrodynamic self-energies of a ls1/2 quark, confined to a static spherical cavity, have been accurately calculated. These quantities are of immediate interest in the M.I.T. bag model. The existing methods to calculate loop diagrams are based on the multiple reflection scheme, in which the zero reflection term is separated out analytically, and evaluated separately. Thus far, there are some indications that this method is unsuitable for the quadratically divergent one loop vacuum polarization. In this thesis we firstly develop a set of Fourier transforms, appropriate to a discussion of renormalization in a cavity. Using these, we renormalize the cavity propagators to one loop for scalar, Dirac, and gauge fields. We then introduce a new computational method to subtract out the divergences, based on dimensional regularization. Using this method, we present results for various loop diagrams. The scalar φ⁴ theory is used as a pedagogical example. We then present the quark self-energy for several low lying cavity modes. Finally we tackle the long standing and hitherto unresolved question of the vacuum polarization. For this we give a detailed discussion of surface divergences, and present results for scalar quantum electrodynamics. We make a suggestion for the implementation of the running coupling constant in the cavity

A perfusion culture system for assessing bone marrow stromal cell differentiation on PLGA scaffolds for bone repair

Biomaterials development for bone repair is currently hindered by the lack of physiologically relevant in vitro testing systems. Here we describe the novel use of a bi-directional perfusion bioreactor to support the long term culture of human bone marrow stromal cells (BMSCs) differentiated on polylactic co-glycolic acid (PLGA). Primary human BMSCs were seeded onto porous PLGA scaffolds and cultured in static vs. perfusion culture conditions for 21 days in osteogenic vs. control media. PLGA scaffolds were osteoconductive, supporting a mature osteogenic phenotype as shown by the upregulation of Runx2 and the early osteocyte marker E11. Perfusion culture enhanced the expression of osteogenic genes Osteocalcin and Osteopontin. Extracellular matrix deposition and mineralisation were spatially regulated within PLGA scaffolds in a donor dependant manner. This, together with the observed upregulation of Collagen type X suggested an environment permissive for the study of differentiation pathways associated with both intramembranous and endochondral ossification routes of bone healing. This culture system offers a platform to assess BMSC behavior on candidate biomaterials under physiologically relevant conditions. Use of this system may improve our understanding of the environmental cues orchestrating BMSC differentiation and enable fine tuning of biomaterial design as we develop tissue-engineered strategies for bone regeneration

Ideology, Hegemony, Discourse: A Critical Review of Theories of Knowledge and Power

For over a century, social theorists have attempted to explain why those who lack economic power consent to hierarchies of social and political power. They have used ideology, hegemony and discourse as key concepts to explain the intersections between the social production of knowledge and the perpetuation of power relations. The Marxist concept of ideology describes how the dominant ideas within a given society reflect the interests of a ruling economic class. In this paper, I trace the movement from this concept of ideology to models of hegemony and discourse. I then trace a second set of ruptures in theories of ideology, hegemony and discourse. Marx and others link ideology to a vision of society dominated by economic class as a field of social power. However, theorists of gender and race have questioned the place of class as the locus of power. I conclude by arguing that key theorists of gender and race Hall, Smith, hooks and Haraway offer a more complex understanding of how our consent to networks of power is produced within contemporary capitalist societies. This argument has important implications for theory and practice directed at destabilizing our consent to power

The clathrin-binding domain of CALM-AF10 alters the phenotype of myeloid neoplasms in mice.

The PICALM (CALM) gene, whose product is involved in clathrin-mediated endocytosis, has been identified in two recurring chromosomal translocations, involving either MLL or MLLT10 (AF10). We developed a mouse model of CALM-AF10(+) leukemia to examine the hypothesis that disruption of endocytosis contributes to leukemogenesis. Exclusion of the C-terminal portion of CALM from the fusion protein, which is required for optimal binding to clathrin, resulted in the development of a myeloproliferative disease, whereas inclusion of this domain led to the development of acute myeloid leukemia and changes in gene expression of several cancer-related genes, notably Pim1 and Crebbp. Nonetheless, the development of leukemia could not be attributed directly to interference with endocytosis or consequential changes in proliferation and signaling. In leukemia cells, full-length CALM-AF10 localized to the nucleus with no consistent effect on growth factor endocyctosis, and suppressed histone H3 lysine 79 methylation regardless of the presence of clathrin. Using fluorescence resonance energy transfer analysis, we show that CALM-AF10 has a propensity to homo-oligomerize, raising the possibility that the function of endocytic proteins involved in chimeric fusions may be to provide dimerization properties, a recognized mechanism for unleashing oncogenic properties of chimeric transcription factors, rather than disrupting the internalization of growth factor receptors

Social Cohesion and Health

More social cohesion has been posited to lead to "more" health; less social cohesion has been posited to lead to "less" health. As well, government performance may influence or be influenced by both social cohesion and health. After defining each of these constructs, we describe changes in measures of these constructs over time (between 1981 and 1990) in Canada, the individual-level factors that are associated with high levels of these measures in Canada, and how these levels compare with those in other G7 countries. We then develop a conceptual framework within which relationships between social cohesion and health can be considered and present the results of new empirical research regarding these relationships in G7 countries. Finally, we synthesize and critically appraise empirical research to inform discussions about the strength of some of these relationships, specifically those involving selected pathways through the determinants of health. We conclude that social cohesion can have significant health consequences (through, for example, known health determinants like income distribution, employment and working conditions, and social support) and that the concepts related to social cohesion don't need reconciliation so much as they need links to the "right" policy environment.

Bulletin No. 305 - The Composition of Sumer Range Plants in Utah

In Utah, a vast industry of livestock grazing, which is the backbone of the state\u27s agriculture, has arisen during the past 75 years. Range land furnishes between 6 and 7 million animal unit months of forage to some 2 1/2 million sheep and 275 thousand range cattle. Income from meat, wool, and range livestock sales in Utah is about $15,801,500 annually, of which$11,700,000 is calculated to be obtained from range lands exclusive of cultivated pastures. These range lands can be used economically in no other way than by grazing livestock and, because of heavy winter snows and protracted dry periods, most of these lands are distinctly seasonal in character. Livestock, then, must be supported for Iong periods upon farm lands or upon other range lands. The animals must be driven or shipped over distances sometimes well in excess of 100 miles from one range to another. The specific seasonal nature of these lands makes important the study of seasonal variations in forage value. That animals can make the most efficient use of the range lands, it is important to understand the forage value, the balance of various chemical constituents, and the importance of deficiencies in the diet of animals existing wholly upon these native plants

AN ASSESSMENT OF THE PROPOSED NEW RISK MANAGEMENT PROGRAMS

The purpose of this assessment as outlined in the terms of reference is: "To obtain an assessment by an independent third party of the expected performance of the proposed new business risk management program's proposed New NISA and production insurance relative to the current set of risk management programming, including NISA, CFIP, crop insurance and companion programs." Within this context, the specific mandate and scope is to assess "the extent to which the current and proposed programs meet the objectives set out by Agriculture Ministers for business risk management programming, as follows: · to ensure programs are responsive to demand and that government dollars are directed to areas of need with respect to income stabilization, disaster mitigation, insurance coverage and investment; · to provide equal treatment for farmers across Canada facing similar risk situations; · to minimize the distortion of farmers' production and marketing decisions; · to focus on management of risks related to the stability of the entire farm and to avoid duplication of payments; · to be relatively simple and easy to understand; and · to facilitate long term planning by farmers."Risk and Uncertainty,

Public Engagement in Climate Communication on China’s Weibo: Network Structure and Information Flows

This article provides an empirical study of public engagement with climate change discourse in China by analysing how Chinese publics participate in the public discussion around two Intergovernmental Panel on Climate Change reports and how individual users interact with state and elite actors on the pre-eminent Chinese microblogging platform Weibo. Using social network analysis methods and a temporal comparison, we examine the structure of climate communication networks, the direction of information flows among multiple types of Weibo users, and the changes in information diffusion patterns between the pre- and post-Paris periods. Our results show there is an increasing yet constrained form of public engagement in climate communication on Weibo alongside China’s pro-environmental transition in recent years. We find an expansion of public engagement as shown by individual users’ increasing influence in communication networks and the diversification of frames associated with climate change discourse. However, we also find three restrictive interaction tendencies that limit Weibo’s potential to facilitate multi-directional communication and open public deliberation of climate change, including the decline of mutually balanced dialogic interactions, the lack of bottom-up information flows, and the reinforcement of homophily tendencies amongst eco-insiders and governmental users. These findings highlight the coexistence of both opportunities and constraints of Weibo being a venue for public engagement with climate communication and as a forum for a new climate politics and citizen participation in China