Photographs, because of their chemical make up, are inherently unstable. The process of degradation is relatively fast and cannot be turned around. This puts both artists and conservators in a... Show morePhotographs, because of their chemical make up, are inherently unstable. The process of degradation is relatively fast and cannot be turned around. This puts both artists and conservators in a difficult position. The idea of reproducing old photographs in order to be able to present them 'the way they were meant when first created'is attractive to many contemporary artists as well to museums. However, the concept of the reproduction of photographic artworks as a fountain of eternal youth that protracts a flawless condition is not without problems. Eternal youth comes at a price. That price varies with each individual work of art. Forever Young examines the reproduction of four photographic artworks as a conservation strategy from the vantage point of a conservator working in a museum of contemporary art. This dissertation explores a vast issue in modern and contemporary art. It is a first attempt in its field and will undoubtedly be start for many future research and scholarly discussion. Show less
Kuiper, M.W.; Ottens, H.J.; Ruijven, J. van; Koks, B.J.; Snoo, G.R. de; Berendse, F. 2015
Field margin management is a common measure employed in Europe to support farmland bird populations. In this study we found and analysed 237 nests of the Skylark Alauda arvensis in the Netherlands... Show moreField margin management is a common measure employed in Europe to support farmland bird populations. In this study we found and analysed 237 nests of the Skylark Alauda arvensis in the Netherlands over a period of 6 years to determine the effects of arable field margins and breeding crop on nest-level reproductive success. Additionally, the effect of field margins on predation was investigated and food availability in crops and field margins was compared. Neither clutch size, nest survival nor nestling body weight were improved by field margin availability, irrespective of the breeding crop used. However, the choice of breeding crop had important effects. Nestling weight was significantly lower in cereals than in grassland and lucerne, corresponding with the low prey densities present in cereals. Nest survival was lowest in grassland due to frequent silage cutting. Predation rates were highest in cereals but were not affected by field margin proximity. The highest reproductive success was achieved in lucerne, which was mown twice a year and retained a suitable height for breeding throughout the breeding season. We conclude that field margins are not sufficient to maintain a Skylark population in this intensively farmed area. The presumably more subtle effects of increased food availability cannot compensate for the high nest failure rates resulting from agricultural operations and predation. In this and similar areas, the provisioning of safe nesting habitat throughout the breeding season is essential to improve breeding performance. Our research suggests that this can be achieved by reducing the frequency of silage cutting on grassland and by increasing the surface area of lucerne. Show less
Raptors in West Africa’s savannas have strongly declined the past four decades and many species now survive only in a few pockets of intact habitat, mostly inside protected areas, while some... Show moreRaptors in West Africa’s savannas have strongly declined the past four decades and many species now survive only in a few pockets of intact habitat, mostly inside protected areas, while some species are on the brink of extinction. Little is known about the processes that sustain raptor populations within increasingly human-transformed savanna landscapes, and clues to the mechanisms and causal drivers behind population declines remain little studied. Moreover, it is unclear how changing conditions differently affect the diverse assemblage of Afrotropical and Palearctic raptors, which depend on the West Africa’s savannas for part or most of their life cycle, and how vulnerability, or adaptability to changing environments, relate to life-history traits such as their mobility, sex, age, body mass, and diet. This thesis quantifies the effects of land transformation on distribution, foraging, diet, and reproductive output of Palearctic and Afrotropical raptors, both migratory and sedentary, in West African savannas, to increase the knowledge that can support conservation efforts directed at the persistence of rich raptor populations in this part of the world. Show less
The general aim of the work described in this thesis is to help explain the variation in ageing by using the life history framework of B. anynana. Each chapter focuses on a different aspect of the... Show moreThe general aim of the work described in this thesis is to help explain the variation in ageing by using the life history framework of B. anynana. Each chapter focuses on a different aspect of the life history, together giving a complete picture of the origins of variation in ageing in this species. A central theme to every chapter is the relative influence of genes, the environment, and how they related to plasticity. A summarising discussion of all chapters, and a perspective on how the ideas in this thesis will contribute to ageing research in the future is also included. Show less
De Europese aal blijkt bij uitstek een langeafstandsspecialist te zijn. Dit is gebleken uit zwemtesten in 22 zwemtunnels. Het kost schieralen slechts 40% van de vetreserves om de 5500-km naar de... Show moreDe Europese aal blijkt bij uitstek een langeafstandsspecialist te zijn. Dit is gebleken uit zwemtesten in 22 zwemtunnels. Het kost schieralen slechts 40% van de vetreserves om de 5500-km naar de paaigronden in de Sargassozee te overbruggen, mogelijk zelfs in slechts drie-en-een-halve maand. Niet alleen dienen vetten als brandstof, ze zijn ook essentieel als energievoorraad voor de toekomstige larven. Het blijkt nu dat zwemmen de afzetting van de vetten in de eitjes op gang brengt. Door te zwemmen beginnen de eicellen van, vooral oudere, alen te ontwikkelen zodat ze kunnen afpaaien zodra ze in de Sargasso zijn aangekomen. De zwemblaasparasiet beschadigt echter de zwemblaas waardoor geïnfecteerde alen minder efficiënt zwemmen en al het vet waarschijnlijk is verbruikt voordat ze de Sargasso bereiken. Een andere verstorende factor zijn de in het vet opgeloste PCB's, die al in zeer lage doses de vroege ontwikkeling van embryo's onmogelijk blijken te maken. Deze twee factoren lijken een belangrijke oorzaak te zijn in de sterke afname van de wilde populatie. Het feit dat we met zwemmen een natuurlijke 'trigger' hebben gevonden van ontwikkeling van de eicellen en dat we in staat zijn geweest schieralen in gevangenschap tot reproductie te brengen biedt hoop voor toekomstige kweek. Show less
