A new approach to quantum backflow

We derive some rigorous results concerning the backflow operator introduced by Bracken and Melloy. We show that it is linear bounded, self adjoint, and not compact. Thus the question is underlined whether the backflow constant is an eigenvalue of the backflow operator. From the position representation of the backflow operator we obtain a more efficient method to determine the backflow constant. Finally, detailed position probability flow properties of a numerical approximation to the (perhaps improper) wave function of maximal backflow are displayed.Comment: 12 pages, 8 figure

The theory and measurement of structural unemployment

The purpose of this thesis is to develop a theoretical framework which could then be used to measure structural unemployment. This is done by first surveying the relevant literature, then developing a theoretical model for the measurement of structural unemployment, and finally applying this model to Canadian data. In the survey of the relevant literature the various approaches are categorized into the causal, the structural maladjustment and the policy approaches. The causal approach involves explaining structural unemployment in terms of the causes of labour displacement. This is considered inadequate because it ignores problems in the labour market adjustment process, whose function is to wipe out the imbalances created by structural dislocations. These problems are considered by the structural maladjustment approach, together with the symptoms of structural maladjustment. It analyzes the forces promoting and impeding the labour market adjustment process. However, these forces are at present not quantifiable. The symptoms of structural maladjustment, on the other hand, are. A favourite method of determining changes in structural maladjustment has been the analysis of the structure of unemployment. This thesis, however, supports the contention that this method is generally misleading. Analyses of long-duration unemployment are also considered not to be useful, but a framework involving the relationship of unemployment to vacancies is seen as fruitful. The policy approach is concerned with the relationship of unemployment and inflation. According to this approach, the degree of structural maladjustment is indicated by the distance of the inflation-unemployment function from the origin. However, there are problems involved in using it to measure structural unemployment, primarily because of the impurities involved in the relationship. The next step is to develop a model which does not depend on proxies for labour demand, but uses variables directly related to the labour market, and has a theoretical rationale. This model must separate the effects of aggregate demand and of structural imbalances on unemployment. It does this by determining the cyclical relationship between the unemployment and vacancy rates and attributing changes which cannot be explained by this relationship to changes in the level of structural imbalances. . This model is then applied to Canadian data. Before that can be done, however, the vacancy rate has to be derived from N.E.S. vacancy data. The ratio of actual vacancies to N.E.S. vacancies is estimated on the basis of the ratio of total hirings to N.E.S. placements. Using the vacancy rate thus estimated, several forms of the relationship between the unemployment and vacancy, rates are empirically tested. The results indicate that very little of the changes in the total unemployment rate are attributable to changes in structural imbalances. Variability in unemployment is largely caused by variability in aggregate demand. However, there appears to have been some upward trend in the structural unemployment rate (defined as the unemployment rate that would prevail if aggregate labour demand were equal to aggregate labour supply), from 3 per cent in the early 1950's to nearly 4 per cent in the 1960's. These results suffer from the uncertainty involved in the estimated vacancy rate, but an analysis of changes in the ratio of total hirings to N.E.S. placements, which was used in the estimation, supports the findings concerning the structural unemployment trend.Arts, Faculty ofVancouver School of EconomicsGraduat

Displacement by development : ethics, rights and responsibilities

For decades, policy-makers in government, development banks and foundations, NGOs, researchers and students have struggled with the problem of how to protect people who are displaced from their homes and livelihoods by development projects. This book addresses these concerns and explores how debates often become deadlocked between 'managerial' and 'movementist' perspectives. Using development ethics to determine the rights and responsibilities of various stakeholders, the authors find that displaced people must be empowered so as to share equitably in benefits rather than being victimized. They propose a governance model for development projects that would transform conflict over displacement into a more manageable collective bargaining process and would empower displaced people to achieve equitable results. Their book will be valuable for readers in a wide range of fields including ethics, development studies, politics and international relations as well as policy making, project management and community development

Synergism between platelet collagen receptors defined using receptor-specific collagen-mimetic peptide substrata in flowing blood

Exposed subendothelial collagen acts as a substrate for platelet adhesion and thrombus formation after vascular injury. Synthetic collagen-derived triple-helical peptides, designated collagen-related peptide (CRP), GFOGER, and VWF-III, can specifically engage the platelet collagen receptors, glycoprotein VI and integrin α2β1, and plasma von Willebrand factor (VWF), respectively. Hitherto, the role of these 3 collagen-binding axes has been studied indirectly. Use of these uniform peptide substrates, rather than collagen fibers, provides independent control of each axis. Here, we use confocal imaging and novel image analysis techniques to investigate the effects of receptor-ligand engagement on platelet binding and activation during thrombus formation under flow conditions. At low shear (100s−1 and 300s−1), both GFOGER and CRP are required for thrombus formation. At 1000s−1, a combination of either CRP or GFOGER with VWF-III induces comparable thrombus formation, and VWF-III increases thrombus deposition at all shear rates, being indispensable at 3000s−1. A combination of CRP and VWF-III is sufficient to support extensive platelet deposition at 3000s−1, with slight additional effect of GFOGER. Measurement of thrombus height after specific receptor blockade or use of altered proportions of peptides indicates a signaling rather than adhesive role for glycoprotein VI, and primarily adhesive roles for both α2β1 and the VWF axis

MTHFD1 interaction with BRD4 links folate metabolism to transcriptional regulation

The histone acetyl reader bromodomain-containing protein 4 (BRD4) is an important regulator of chromatin structure and transcription, yet factors modulating its activity have remained elusive. Here we describe two complementary screens for genetic and physical interactors of BRD4, which converge on the folate pathway enzyme MTHFD1 (methylenetetrahydrofolate dehydrogenase, cyclohydrolase and formyltetrahydrofolate synthetase 1). We show that a fraction of MTHFD1 resides in the nucleus, where it is recruited to distinct genomic loci by direct interaction with BRD4. Inhibition of either BRD4 or MTHFD1 results in similar changes in nuclear metabolite composition and gene expression; pharmacological inhibitors of the two pathways synergize to impair cancer cell viability in vitro and in vivo. Our finding that MTHFD1 and other metabolic enzymes are chromatin associated suggests a direct role for nuclear metabolism in the control of gene expression