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Met dit rapport brengt de Werkgroep Discontovoet advies uit over de discontovoeten die dienen te worden gebruikt in Maatschappelijke Kosten-Baten Analyses (MKBA’s).

Three different approaches to calculating the electric potential in an inhomogeneous dielectric next to vacuum due to a charge distribution built up by the electron beam are investigated. An analytical solution for the electric potential cannot be found by means of the image charge method or Fourier analysis, both of which do work for a homogenous dielectric with a planar interface to vacuum. A Born approximation gives a good approach to the real electric potential in a homogenous dielectric up to a relative dielectric constant of 5. With this knowledge the electric potential of an inhomogenous dielectric is calculated. Also the electric field is calculated by means of a particle-mesh method. Some inhomogeneous dielectric configurations are calculated and their bound charges are studied. Such a method can yield accurate calculations of the electric potential and can give quantitative insight in the charging process. A capacitor model is described to estimate the potential due to the charge build up. It describes the potential build up in the first microseconds of the charging. Thereafter, it seems that more processes have to be taken into account to describe the potential well. This potential can further be used in a macroscopic approach to the collective motion of the electrons described by the Boltzmann transport equations or a derived density model, which can be a feasible alternative approximation to the more commonly used Monte-Carlo simulation of individual trajectories.

Metal nanorods and nanowires have great potential in a wide range of fields, because of their tunable (by shape and size) optical and magnetic properties. We present and discuss an unique way for producing perfectly parallel nanorods and -wires that are embedded in a solid. Starting from monodisperse spherical Au nanocolloids (15-50 nm diameter) in a silica matrix we show that the colloids are shaped controllably into rods -- and at later stages -- wires under heavy-ion irradiation above a threshold energy loss of ~6keV/nm. The threshold coincides with the formation of a continuous molten ion track, as follows from ion track temperature calculations. Nanowires of ~10nm diameter with lengths up to several hundred nanometer form and align parallel to the ion beam in the fluence regime of 1014-1015 ions/cm2. Based on experiments with different colloid sizes and concentrations we conclude that all Au nanospheres initially elongate into nanorods, with their long axis along the ion track. Above a critical fluence (e.g. 1x1014/cm2 for 54 MeV Ag) individual nanorods disintegrate while others continue to grow by uptake of the atoms of the disintegrated particles. This novel type of ripening process is corroborated by 3D kinetic Monte Carlo simulations. Based on atomistic simulations we suggest that the lengthening is a result of thermocapillarity, which drives material of a gold nanosphere that is touched by an ion track from the hot equator to the colder pole regions. Temperature gradients of several billions Kelvin per cm can be reached, conditions that are similar to femtosecond laser processing of Au layers [1] where frozen nanojets have been observed. [1] F. Korte, J. Koch, and B.N. Chichkov, Appl.Phys. A 79 (2004) 879-881

We develop multivariate measures of synchronicity and co-movement of business cycles. In addition to synchronicity, the co-movement measure takes differences between cycle amplitudes into account that have been overlooked in most previous studies. We apply the new measures to the euro area. Synchronicity and co-movement for the region as a whole do not exhibit a clear upward tendency. Although several countries saw the similarity of their business cycle vis-`a-vis the euro area reference cycle increase, national business cycles remain fairly diverse. Changes in business cycle amplitudes cause most of the observed change in cycle co-movement.

Analysis of the transcriptome, the total of all expressed RNA transcripts in a cell or an organism, contributes to our understanding of gene regulation during development and disease processes and is therefore of great importance in the field of genomic research. This thesis focuses on the analysis of transcriptome complexity during infectious disease and cancer. The zebrafish was applied as an immunological model organism, due to the remarkable similarities of its immune system to that of human. The studies took advantage of novel opportunities for transcriptome profiling provided by recent developments in microarray and next generation sequencing technology that have made an enormous impact on biology. In addition to studying expression of protein coding genes, the work addressed regulatory functions of microRNAs, small non-coding RNAs playing important roles in the function of the immune system and other processes. The transcriptome data provide a valuable reference set of infection-responsive genes and microRNAs in zebrafish models and have identified microRNAs conserved between human and zebrafish liver cancer. These genomic data sets provide a strong basis for future applications of zebrafish as an infection and cancer model and contribute to the understanding of pathogenesis and the development of novel strategies for disease treatment.

YouTubers are popular among young people and produce plentiful health content. Research suggests YouTube health content varies in quality and social media health interventions remain scarce. However, popular media and public health organisations are increasingly recognising YouTubers’ potential influence as a source of health information for young people. Little research has considered the nature of YouTuber content, young people’s engagement or YouTubers’ motives for producing it. This programme of research sought to examine the role professional YouTubers play in young people’s health behaviours in the UK. The research adopted a four-stage mixed methods sequential design. A questionnaire with 13-18 year olds (n=931) provided a sampling frame for three qualitative studies. These were a netnographic analysis of health-related videos (n=133) from 7 UK YouTubers, 8 focus groups with 13-18 year olds (n=85) and semi-structured interviews with UK YouTubers (n=3). Participating young people were from one county in North West England. The findings confirm YouTubers are a recognised source of health information for young people. YouTubers produce content on a range of topics with numerous perceived benefits. A successful trait is YouTubers’ ability to foster a sense of community; this familiarity and trust allows them to endorse health-related products or behaviours. YouTubers were thus viewed as role models by young viewers. Several complexities of YouTuber health content production were also highlighted. Young people and YouTubers were concerned giving advice beyond their expertise could lead to misdiagnosis, triggering or worsening of health conditions. There was an inherent tension between self-promotion and health promotion with YouTubers reluctant to expose themselves to criticism, compromise their brand and authenticity or engage in self-regulatory practices. The distinction between commercial, NHS or charity sponsored, and unsponsored content and sponsor intentions (health promotion or commercial) were not always clear. The impact of YouTuber health content is therefore dependent on young people’s critical literacy skills, which increased with age. Overall, the research confirms YouTubers’ considerable potential to contribute to young people’s health improvement interventions, but successful interventions must consider factors that affect young people’s engagement and YouTubers’ production of health content.