Dual exposure interferometry

The application of dual exposure differential interferometry to gas dynamics and flow visualization is discussed. A differential interferometer with Wallaston prisms can produce two complementary interference fringe systems, depending on the polarization of the incident light. If these two systems are superimposed on a film, with one exposure during a phenomenon, the other before or after, the phenomenon will appear on a uniform background. By regulating the interferometer to infinite fringe distance, a resolution limit of approximately lambda/500 can be obtained in the quantitative analysis of weak phase objects. This method was successfully applied to gas dynamic investigations

Tong's spectrum for Rosen continued fractions

The Rosen fractions are an infinite set of continued fraction algorithms, each giving expansions of real numbers in terms of certain algebraic integers. For each, we give a best possible upper bound for the minimum in appropriate consecutive blocks of approximation coefficients (in the sense of Diophantine approximation by continued fraction convergents). We also obtain metrical results for large blocks of ``bad'' approximations.Comment: 22 pages, 5 figure

Fibrations with few rational points

We study the problem of counting the number of varieties in families which have a rational point. We give conditions on the singular fibres that force very few of the varieties in the family to contain a rational point, in a precise quantitative sense. This generalises and unifies existing results in the literature by Serre, Browning-Dietmann, Bright-Browning-Loughran, Graber-Harris-Mazur-Starr, et al.Comment: 34 pages. Major revision. More details added and examples section moved to the end of the paper. Main theorems unchanged. To appear in GAF

Bias for the (un)attractive self: on the role of attention in causing body (dis)satisfaction

Objective: Body dissatisfaction plays a key role in the maintenance of eating disorders, and selective attention might be crucial for the origin of body dissatisfaction. A. Jansen, C. Nederkoorn, and S. Mulkens (2005) showed that eating disorder patients attend relatively more to their own unattractive body parts, whereas healthy controls attend relatively more to their own attractive body parts. In 2 studies, we investigated whether this bias in selective attention is causal to body dissatisfaction and whether an experimentally induced bias for attractive body parts might lead to increased body satisfaction in women who are highly dissatisfied with their bodies. Design: We used a between-subjects design in which participants were trained to attend to either their self-defined unattractive body parts or their self-defined attractive body parts by use of an eye tracker. Main Outcome Measures: State body and weight satisfaction. Results: Inducing a temporary attentional bias for self-defined unattractive body parts led to a significant decrease in body satisfaction and teaching body-dissatisfied women to attend to their own attractive body parts led to a significant increase in body satisfaction. Conclusion: Selective attention for unattractive body parts can play a role in the development of body dissatisfaction, and changing the way one looks may be a new way for improving body dissatisfaction in women. (PsycINFO Database Record (c) 2011 APA, all rights reserved) (journal abstract

Pseudo-split fibres and arithmetic surjectivity

Let f : X → Y be a dominant morphism of smooth, proper and geometrically integral varieties over a number field k, with geometrically integral generic fibre. We give a necessary and sufficient geometric criterion for the induced map X ( k v ) → Y ( k v ) to be surjective for almost all places v of k. This generalises a result of Denef which had previously been conjectured by Colliot-Th ́el`ene, and can be seen as an optimal geometric version of the celebrated Ax–Kochen theorem

Knowledge diffusion from FDI and intellectual property rights

We study the extent to which a country's strength of Intellectual Property Rights (IPR) protection mediates knowledge spillovers from Foreign Direct Investment (FDI). Following the opposing views in the IPR debate, we propose a negative effect of IPR strength on unintentional horizontal (intra-industry) knowledge diffusion. Using a unique firm-level dataset of large, publicly traded firms in 22 (mostly) developed countries, we find partial support for these expectations. Strong IPR indeed reduces horizontal knowledge diffusion, while it stimulates backward (to suppliers) knowledge diffusion. Somewhat unexpectedly however, we also find that forward (to customers) knowledge diffusion decreases with IPR strength. In general, and in line with earlier literature, the results regarding backward knowledge diffusion are most robust to changes in model specification. Our results contribute to the debate regarding the desirability of strengthening national IPR systems, and suggest that local firms might indeed benefit from this through their (backward) linkages with multinationals. Additionally, our results suggest that the moderating effect of IPR strength might partly explain the inconclusive results in the FDI knowledge diffusion literature

Can Material Passports lower financial barriers for structural steel re-use?

The building and construction sector is responsible for more than half of global steel consumption. Recycling is common practice. Yet, this is an energy intensive process, even when using the best currently available technology. A strategy that avoids energy use for remelting and significantly reduces negative environmental impacts is re-use. Steel element re-use is technically feasible and economically attractive in certain cases. However, re-use rates in the UK remain low. Cost and timing are identified to be among the main barriers for re-use across the structural steel value chain. Re-used steel is estimated to be about 8-10% more expensive than new steel, taking into account all required reconditioning processes. This study investigates how data/information services like BAMB Material Passports can facilitate structural steel re-use in the UK by lowering financial barriers. It shows that relevant data has the potential of reducing costs in sourcing, testing, reconditioning and fabrication, ranging from 150-1000 £/t, depending on the re-use path followed (remanufacture or direct re-use of elements/structures). Key stakeholder groups are stockists and fabricators, which will be both the suppliers and customers of the data. It should be noted that data alone is not sufficient to overcome all barriers. Next to shortening or vertical integration of the supply chain, value redistribution across the chain can align incentives of different stakeholders. Regulations and perceptions (on quality) also play a key role. Finally, reversible design/design for dismantling can be a game changer in the transition towards more structural steel re-use, since it can significantly reduce deconstruction costs