Noncommutative phenomena in flat and curved space-times

Includes bibliographical references (leaves 88-92).This thesis aims to explore several facets of noncommutative geometry which arise in physics. In particular, our focus will be on string-inspired noncommutativity, and we will at all times try to justify the noncommutative models we study from a stringy perspective

Psychosocial impact of undergoing prostate cancer screening for men with BRCA1 or BRCA2 mutations.

OBJECTIVES: To report the baseline results of a longitudinal psychosocial study that forms part of the IMPACT study, a multi-national investigation of targeted prostate cancer (PCa) screening among men with a known pathogenic germline mutation in the BRCA1 or BRCA2 genes. PARTICPANTS AND METHODS: Men enrolled in the IMPACT study were invited to complete a questionnaire at collaborating sites prior to each annual screening visit. The questionnaire included sociodemographic characteristics and the following measures: the Hospital Anxiety and Depression Scale (HADS), Impact of Event Scale (IES), 36-item short-form health survey (SF-36), Memorial Anxiety Scale for Prostate Cancer, Cancer Worry Scale-Revised, risk perception and knowledge. The results of the baseline questionnaire are presented. RESULTS: A total of 432 men completed questionnaires: 98 and 160 had mutations in BRCA1 and BRCA2 genes, respectively, and 174 were controls (familial mutation negative). Participants' perception of PCa risk was influenced by genetic status. Knowledge levels were high and unrelated to genetic status. Mean scores for the HADS and SF-36 were within reported general population norms and mean IES scores were within normal range. IES mean intrusion and avoidance scores were significantly higher in BRCA1/BRCA2 carriers than in controls and were higher in men with increased PCa risk perception. At the multivariate level, risk perception contributed more significantly to variance in IES scores than genetic status. CONCLUSION: This is the first study to report the psychosocial profile of men with BRCA1/BRCA2 mutations undergoing PCa screening. No clinically concerning levels of general or cancer-specific distress or poor quality of life were detected in the cohort as a whole. A small subset of participants reported higher levels of distress, suggesting the need for healthcare professionals offering PCa screening to identify these risk factors and offer additional information and support to men seeking PCa screening

The Costs of Strategic Adaptation to Climate Variability and Change.: New Methodologies and Interdisciplinary Approaches in Global Change Research (International Symposium, Porquerolles, France 2008).

Fonds audiovisuel du programme "ESCoM-AAR" (Equipe Sémiotique Cognitive et nouveaux Médias - Archives Audiovisuelles de la Recherche. Paris, France, 2000 - 2016).A simple theoretical model of the process of strategic adaptation to climate change is proposed. Climate change is represented by a non-stationary Markov process on the space of climate states, and strategic adaptation by a simple resource allocation task in which agents incur costs when moving resources from one activity to another. A stationary analysis allows diagnostics that quantify the net costs of climate change, and the long-run benefits to adaptation, to be defined. A full dynamic analysis of the model allows for the computation of the costs of negotiating the transition between two stationary climate regimes. We analyze the dependence of these adaptation costs on the behavioural parameters of the model, and the costs of adjusting resources from one activity to another. We find that adaptation costs have a complex and counterintuitive dependence on adjustment costs, and can be more sensitive to the details of the climate change process than adaptation benefits are. This has important implications for adaptation planning, and understanding the linkages between adaptation and climate change mitigation

Ultra-Sensitive determination of pesticides via cholinesterase-based sensors for environmental analysis.

This review is focussed towards the development of acetylcholinesterase enzymatic based biosensors for the quantification of trace concentrations of highly toxic pesticides via their inhibitory effect on the enzyme. Initial results were obtained using wild-type enzymes which have a broad spectrum of susceptibility to a variety of pesticides. The sensitivity and selectivity of the enzyme activity was improved by development and screening of a wide range of mutant enzymes. Optimal enzymes were then exploited within a range of sensor formats. A range of immobilisation techniques including adsorption based approaches, binding via proteins and entrapment within conducting polymers were all studied. The incorporation of stabilisers and co-factors were utilised to optimise electrode performance and stability - with both planar and microelectrode geometries being developed. Reproducible quantification of pesticides could be obtained at concentrations down to 10-17 M, representing a detection limit hitherto unavailable

Structure-Function Analysis of the Presumptive Arabidopsis Auxin Permease AUX1

We have investigated the subcellular localization, the domain topology, and the amino acid residues that are critical for the function of the presumptive Arabidopsis thaliana auxin influx carrier AUX1. Biochemical fractionation experiments and confocal studies using an N-terminal yellow fluorescent protein (YFP) fusion observed that AUX1 colocalized with plasma membrane (PM) markers. Because of its PM localization, we were able to take advantage of the steep pH gradient that exists across the plant cell PM to investigate AUX1 topology using YFP as a pH-sensitive probe. The YFP-coding sequence was inserted in selected AUX1 hydrophilic loops to orient surface domains on either apoplastic or cytoplasmic faces of the PM based on the absence or presence of YFP fluorescence, respectively. We were able to demonstrate in conjunction with helix prediction programs that AUX1 represents a polytopic membrane protein composed of 11 transmembrane spanning domains. In parallel, a large aux1 allelic series containing null, partial-loss-of-function, and conditional mutations was characterized to identify the functionally important domains and amino acid residues within the AUX1 polypeptide. Whereas almost all partial-loss-of-function and null alleles cluster in the core permease region, the sole conditional allele aux1-7 modifies the function of the external C-terminal domain