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The pervasive phenomenon of adaptivity in face-to-face interaction is described inconsistently, using numerous concepts (e.g. alignment/attunement/complementarity/imitation/reciprocity/scaffolding/synchrony), impeding the streamlining of adaptivity research. We explored 33 adaptivity concepts and various adaptivity theories from different fields. We developed a theory-based conceptual framework consisting of two key dimensions. Relatedness refers to how people’s actions should relate to each other to be considered adaptive and is described in terms of sameness (e.g. both friendly), oppositeness (e.g. dominant/submissive), or specified attentiveness (dissimilar acts). Responsivity refers to the timing of people’s actions (sequential/simultaneous). The framework helps to understand what key elements adaptivity consists of. The framework can help transcending the concept and discipline level and examining and synthesizing research pertaining to adaptivity with similar dimensional characteristics.

Hot-humid environmental conditions have a negative impact on exercise performance and increase the risk of exertional heat illness. To attenuate the adverse effects of heat stress, athletes can adopt heat mitigation strategies such as heat acclimation and cooling. In this thesis, we assessed individual responsiveness to exercise under heat stress and heat mitigation strategies. First, we focused on heat-induced performance decrements in able-bodied and para-athletes. In Chapter 2, we observed that, for both able-bodied and para-athletes, performance was substantially impaired in hot-humid compared to temperate conditions. We did, however, observe considerable inter-individual variability, suggesting that some athletes need to invest more in heat mitigation strategies (i.e., cooling and heat acclimation) than others. Second, we focused on heat acclimation in recreational athletes. In Chapter 3, we demonstrated that the magnitude of adaptations following humid heat acclimation varied across individuals. We found that individuals with a relatively large body mass showed large sweat rate adaptations, whereas individuals with a relatively small body mass showed large heart rate adaptations. In Chapter 4, we observed that humid heat acclimation did not negatively affect salivary immunoglobulin-A (i.e., an important biomarker of the mucosal immune system), self-reported respiratory illness symptoms, and self-reported wellness parameters. Third, we focused on heat mitigation strategies in para-athletes. Para-athletes with a spinal cord injury perform upper-body exercise, and therefore lower-body cooling may be convenient. However, in Chapter 5, we observed that for these athletes, lower-body cooling was less effective in lowering heat strain compared to upper-body cooling. In Chapter 6, we observed that many para-athletes at the Tokyo 2020 Paralympic Games used heat acclimation and cooling strategies, which may have contributed to the low incidence of exertional heat illness. Altogether, the observations in this thesis indicate that heat mitigation needs and responsiveness vary across athletes, emphasizing that a one-size-fits-all heat mitigation approach may be suboptimal. Practitioners are encouraged to measure (thermo)physiological responses of individual athletes in the lab and/or field to determine their personal heat mitigation needs and responsiveness. Future studies should aim to further elucidate what factors influence the individual responsiveness to exercise under heat stress, cooling, and heat acclimation.

Hot-humid environmental conditions have a negative impact on exercise performance and increase the risk of exertional heat illness. To attenuate the adverse effects of heat stress, athletes can adopt heat mitigation strategies such as heat acclimation and cooling. In this thesis, we assessed individual responsiveness to exercise under heat stress and heat mitigation strategies. First, we focused on heat-induced performance decrements in able-bodied and para-athletes. In Chapter 2, we observed that, for both able-bodied and para-athletes, performance was substantially impaired in hot-humid compared to temperate conditions. We did, however, observe considerable inter-individual variability, suggesting that some athletes need to invest more in heat mitigation strategies (i.e., cooling and heat acclimation) than others. Second, we focused on heat acclimation in recreational athletes. In Chapter 3, we demonstrated that the magnitude of adaptations following humid heat acclimation varied across individuals. We found that individuals with a relatively large body mass showed large sweat rate adaptations, whereas individuals with a relatively small body mass showed large heart rate adaptations. In Chapter 4, we observed that humid heat acclimation did not negatively affect salivary immunoglobulin-A (i.e., an important biomarker of the mucosal immune system), self-reported respiratory illness symptoms, and self-reported wellness parameters. Third, we focused on heat mitigation strategies in para-athletes. Para-athletes with a spinal cord injury perform upper-body exercise, and therefore lower-body cooling may be convenient. However, in Chapter 5, we observed that for these athletes, lower-body cooling was less effective in lowering heat strain compared to upper-body cooling. In Chapter 6, we observed that many para-athletes at the Tokyo 2020 Paralympic Games used heat acclimation and cooling strategies, which may have contributed to the low incidence of exertional heat illness. Altogether, the observations in this thesis indicate that heat mitigation needs and responsiveness vary across athletes, emphasizing that a one-size-fits-all heat mitigation approach may be suboptimal. Practitioners are encouraged to measure (thermo)physiological responses of individual athletes in the lab and/or field to determine their personal heat mitigation needs and responsiveness. Future studies should aim to further elucidate what factors influence the individual responsiveness to exercise under heat stress, cooling, and heat acclimation.

Tipping points are an emerging concept in climate change research and communication. However, previous research has strongly focussed on tipping points in biophysical systems, which left the potential for climate change induced socio-economic tipping points (SETPs) mostly unexplored. The objective of this thesis is to identify and assesses SETPs in order to support decision making on climate policy. A SETP is defined as “a climate change induced, abrupt change of a socio-economic system, into a new, fundamentally different state”. SETPs are characterised by: (1) stable states at two sides of a threshold; (2) a non-linear change mechanism, and (3) rapid change while passing the threshold. Examples are: the collapse of winter sports tourism, farmland abandonment, and sea-level rise-induced migration. The clearest examples of SETPs are likely to be found on small scale homogeneous systems, that can exhibit a system-wide uniform response to a climate driver. When modelling SETPs, there is an extra layer of complexity compared to biophysical tipping points, because of the complex dynamic character of the socio-economic system and the fact that humans proactively and autonomously alter the system to anticipate biophysical change. This thesis presents a stepwise approach for identification and assessment of SETPs, which in seven steps guides the researcher through key study design choices. The first application is urban water security. The essence of urban water security lies in an adequate response to partly inevitable system pressures, with well-functioning infrastructure that prevents adverse impacts such as flood damage. At the same time, in cities under pressure, like Amsterdam and Rotterdam, flood pressures may always propagate along the cause-effect chain via an unexpected mechanism. For example, a flood or near-miss experience could lead to the SETP of an abrupt house price collapse. Stepwise SETP-assessment shows that house price collapses could happen under conditions of high-end sea level rise, reactive flood risk management, and slow measure implementation. A new policy insight is that this SETP may be avoided by managing risk perceptions; when all buyers and sellers on the housing market are aware of gradual changes in flood risk, large fluctuations in risk perceptions and related house price booms and busts may be prevented. The second application field is the road transport infrastructure of thirty European countries. The SETP investigated is an abrupt large-scale malfunctioning of the road network from a river flood event. National-scale SETPs are most likely in small mountainous countries like Slovenia, Macedonia and Albania, where the 5% least favourable small-scale flood events may already disrupt some 30-40% of the preferred routes between major economic regions. Targeted flood proofing of a few critical weak spots by road operators could be a relatively easy, yet very effective, way to enhance the network robustness. Many countries have certain regions that could abruptly become poorly accessible during river floods. Such regional-scale tipping points seem to be much more likely and policy relevant than large national-scale disruptions. The third application is winter sports tourism. For six ski resorts in the Swiss Alps, the SETP of an abrupt bankruptcy is investigated. Bankruptcy might follow when in consecutive years, the number of days with good snow conditions falls below a critical threshold. The effectiveness of incremental and more transformative adaptation, resp. artificial snowmaking and year-round business model diversification, is explicitly modelled. The resulting policy insight is that beyond 2050, low-altitude resorts cannot avoid SETPs with artificial snow making alone, and can only survive with economic diversification towards year-round, less snow-dependent activities. Higher-altitude resorts must be aware that ski lift and real estate investments come with a long-term commitment to artificial snow making to avoid SETPs.

Tipping points are an emerging concept in climate change research and communication. However, previous research has strongly focussed on tipping points in biophysical systems, which left the potential for climate change induced socio-economic tipping points (SETPs) mostly unexplored. The objective of this thesis is to identify and assesses SETPs in order to support decision making on climate policy. A SETP is defined as “a climate change induced, abrupt change of a socio-economic system, into a new, fundamentally different state”. SETPs are characterised by: (1) stable states at two sides of a threshold; (2) a non-linear change mechanism, and (3) rapid change while passing the threshold. Examples are: the collapse of winter sports tourism, farmland abandonment, and sea-level rise-induced migration. The clearest examples of SETPs are likely to be found on small scale homogeneous systems, that can exhibit a system-wide uniform response to a climate driver. When modelling SETPs, there is an extra layer of complexity compared to biophysical tipping points, because of the complex dynamic character of the socio-economic system and the fact that humans proactively and autonomously alter the system to anticipate biophysical change. This thesis presents a stepwise approach for identification and assessment of SETPs, which in seven steps guides the researcher through key study design choices. The first application is urban water security. The essence of urban water security lies in an adequate response to partly inevitable system pressures, with well-functioning infrastructure that prevents adverse impacts such as flood damage. At the same time, in cities under pressure, like Amsterdam and Rotterdam, flood pressures may always propagate along the cause-effect chain via an unexpected mechanism. For example, a flood or near-miss experience could lead to the SETP of an abrupt house price collapse. Stepwise SETP-assessment shows that house price collapses could happen under conditions of high-end sea level rise, reactive flood risk management, and slow measure implementation. A new policy insight is that this SETP may be avoided by managing risk perceptions; when all buyers and sellers on the housing market are aware of gradual changes in flood risk, large fluctuations in risk perceptions and related house price booms and busts may be prevented. The second application field is the road transport infrastructure of thirty European countries. The SETP investigated is an abrupt large-scale malfunctioning of the road network from a river flood event. National-scale SETPs are most likely in small mountainous countries like Slovenia, Macedonia and Albania, where the 5% least favourable small-scale flood events may already disrupt some 30-40% of the preferred routes between major economic regions. Targeted flood proofing of a few critical weak spots by road operators could be a relatively easy, yet very effective, way to enhance the network robustness. Many countries have certain regions that could abruptly become poorly accessible during river floods. Such regional-scale tipping points seem to be much more likely and policy relevant than large national-scale disruptions. The third application is winter sports tourism. For six ski resorts in the Swiss Alps, the SETP of an abrupt bankruptcy is investigated. Bankruptcy might follow when in consecutive years, the number of days with good snow conditions falls below a critical threshold. The effectiveness of incremental and more transformative adaptation, resp. artificial snowmaking and year-round business model diversification, is explicitly modelled. The resulting policy insight is that beyond 2050, low-altitude resorts cannot avoid SETPs with artificial snow making alone, and can only survive with economic diversification towards year-round, less snow-dependent activities. Higher-altitude resorts must be aware that ski lift and real estate investments come with a long-term commitment to artificial snow making to avoid SETPs.

In our daily lives, we have to process information about all kinds of quantities such as the set size of a group of items (i.e., numerosity), time and size, among others. We have previously reported specialized neurons in our brain which respond selectively to or ‘prefer’ a specific number of items such as one, two or three. These neurons are organized topographically which means that these neurons are laid out in a shape that allows those most closely related to communicate and interact over the shortest possible distance in the brain. The general research goal of this thesis was to examine the properties of numerosity-tuned neural populations, and numerosity perception as part of a generalized quantity system by investigating the possibility of shared, tuned mechanisms between numerosity and time, and other quantities and sensory modalities. We first examined whether and how the selective response or preference of these numerosity selective neurons can change based on recent sensory experience. We used the method of adaptation and ultra-high-field 7 Tesla fMRI, where participants were repeatedly shown a low or high numerosity so to adapt the numerosity-selective neural populations. Sensory adaptation, makes the appearance of subsequently presented stimuli appear more different from the adapting stimulus than they actually are. This method is a powerful tool which allows us to make inferences about the existence of specialized neurons in the brain which respond selectively to the adapting stimuli. We show the dynamic nature of numerosity selective neural populations, where neural numerosity selectivity was altered systematically in all numerosity selective brain areas. Based on findings showing brain regions which process more than one type of quantity, such as numerosity and time, we proceeded to use cross-adaptation to numerosity and time to study whether neural populations selective for numerosity or time interact. We found an unbalanced interaction between numerosity and time where adaptation to time affected numerosity perception but not the other way around. After finding this interaction between neurons selective for processing numerosity and time, further experiments showed that the neural populations underlying the effect of adaptation to time on numerosity perception are partially distinct from those underlying the effect of the time of adaptation on numerosity perception. Collectively, these results highlight that there are partially overlapping neural mechanisms which are dedicated for processing both numerosity and time. We propose that neurons which are selective or are ‘tuned’ to different quantities such as number, time or size are fundamental to understanding quantity perception. We illustrate how the properties of quantity-tuned neurons can underlie various perceptual phenomena. We further show that quantity-tuned neurons are organized in distinct but overlapping neural networks. We suggest that this overlap in tuning provides the neural basis for perceptual interactions between different quantities.

In our daily lives, we have to process information about all kinds of quantities such as the set size of a group of items (i.e., numerosity), time and size, among others. We have previously reported specialized neurons in our brain which respond selectively to or ‘prefer’ a specific number of items such as one, two or three. These neurons are organized topographically which means that these neurons are laid out in a shape that allows those most closely related to communicate and interact over the shortest possible distance in the brain. The general research goal of this thesis was to examine the properties of numerosity-tuned neural populations, and numerosity perception as part of a generalized quantity system by investigating the possibility of shared, tuned mechanisms between numerosity and time, and other quantities and sensory modalities. We first examined whether and how the selective response or preference of these numerosity selective neurons can change based on recent sensory experience. We used the method of adaptation and ultra-high-field 7 Tesla fMRI, where participants were repeatedly shown a low or high numerosity so to adapt the numerosity-selective neural populations. Sensory adaptation, makes the appearance of subsequently presented stimuli appear more different from the adapting stimulus than they actually are. This method is a powerful tool which allows us to make inferences about the existence of specialized neurons in the brain which respond selectively to the adapting stimuli. We show the dynamic nature of numerosity selective neural populations, where neural numerosity selectivity was altered systematically in all numerosity selective brain areas. Based on findings showing brain regions which process more than one type of quantity, such as numerosity and time, we proceeded to use cross-adaptation to numerosity and time to study whether neural populations selective for numerosity or time interact. We found an unbalanced interaction between numerosity and time where adaptation to time affected numerosity perception but not the other way around. After finding this interaction between neurons selective for processing numerosity and time, further experiments showed that the neural populations underlying the effect of adaptation to time on numerosity perception are partially distinct from those underlying the effect of the time of adaptation on numerosity perception. Collectively, these results highlight that there are partially overlapping neural mechanisms which are dedicated for processing both numerosity and time. We propose that neurons which are selective or are ‘tuned’ to different quantities such as number, time or size are fundamental to understanding quantity perception. We illustrate how the properties of quantity-tuned neurons can underlie various perceptual phenomena. We further show that quantity-tuned neurons are organized in distinct but overlapping neural networks. We suggest that this overlap in tuning provides the neural basis for perceptual interactions between different quantities.

Coastal floods are one of the deadliest and costliest of natural hazards, triggering or contributing to economic disruption, displacement, (mental) health implications, environmental disasters, poverty traps, and geomorphic change. In the coming century, coastal communities are projected to face increases in coastal flood risk. To prevent this increase in coastal flood risk, or even reduce risk below today’s levels, adaptation strategies are necessary. To make informed decisions on what measures to take, it is important to better understand the effectiveness of such coastal flood risk adaptation strategies, preferably beyond just monetary terms. Therefore, the overall aim of this thesis is to disentangle drivers of coastal flood risk and assess costs and benefits of adaptation strategies. By doing so, the thesis improves upon conventional flood risk assessments by taking steps into the direction of integrated and holistic assessments that include Nature-based Solutions and valuing of adaptation beyond monetary terms. This thesis uses artificial intelligence in the form of deep learning to construct a model to predict storm surges (which may lead to coastal flooding) at the global scale. Next to this, a risk model has been constructed to assess the effectiveness of adaptation strategies (based on structural measures, Nature-based Solutions, or a combination which is called “hybrid” measures). We assess risk by using projections of sea-level rise, socioeconomic change, subsidence, foreshore vegetation and restoration potential. Next to this we use vulnerability data, like poverty dynamics, to assess effectiveness of adaptation measures beyond monetary values. The results show that EAD increases by a factor of 150 between 2010 and 2080, if no adaptation were to take place, and that 15 countries account for approximately 90% of this increase. Moreover, sea-level rise contributed the most to the increase in coastal flood risk, but socioeconomic change and subsidence also play an important role at the regional scale. Furthermore, the results show that implementing Nature-based Solution, like conservation and restoration of foreshore vegetation, can contribute a large share to reduce flood risk and will next to structural measures, likes dikes and levees, increase the feasibility of adaptation strategies for two-thirds (68%) of the regions assessed. Moreover, we show that restoration of mangroves contribute to the safeguarding of communities by providing coastal flood protection benefits. Therefore, implementing adaptation in low- and middle-income countries could contribute to the resilience of people in poverty, poverty alleviation and help tackle poverty traps. Overall, the results of this thesis contribute to international initiatives such as the Sendai Framework for Disaster Risk Reduction and can be used to inform policy makers and development agencies on risks from global to regional level. In order to bridge the gap between academia and the risk management community, we integrated the results into the Aqueduct Global Floods webtool (www.wri.org/floods). This webtool allows any user to examine current and future risk, as well as the benefits of strucutral flood protection at the sub-national scale. Implementing adaptation measures, such as mangrove restoration, in LMICs could contribute to the resilience of people in poverty, decrease the risk of displacement and migration, and tackle poverty traps. The loss of these ecosystems disproportionally affects vulnerable groups and communities that live close to the coast and often heavily depend on natural resources. The results can help policymakers to assess the threat of coastal flooding and design sustainable adaptation measures considering poverty dynamics.

Dat hittestress een belangrijke uitdaging is in klimaatadaptatie bleek wel weer in de laatste weken van juli en augustus waarbij hitterecords sneuvelden. In Nederland wordt relatief veel gemeten in de buitenlucht, maar ook steeds meer in woningen om hittestress te bepalen. Meetstations die in woonwijken en woningen zijn aangebracht, maten afgelopen juli en augustus hoge temperaturen met gevoelstemperaturen rond 50 ˚C. Er is actie nodig om aangedragen voorbeelden toe te passen.

Dat hittestress een belangrijke uitdaging is in klimaatadaptatie bleek wel weer in de laatste weken van juli en augustus waarbij hitterecords sneuvelden. In Nederland wordt relatief veel gemeten in de buitenlucht, maar ook steeds meer in woningen om hittestress te bepalen. Meetstations die in woonwijken en woningen zijn aangebracht, maten afgelopen juli en augustus hoge temperaturen met gevoelstemperaturen rond 50 ˚C. Er is actie nodig om aangedragen voorbeelden toe te passen.

Literary historians have often noted the ‘conventional’ nature of the 14th-century Middle Dutch verse romance or ridderroman. While the corpus has long been depreciated as derivative, a mixture of older romance motifs amplified into sometimes grotesque proportions: ‘epic in decay’, this view has slowly been reconsidered. The complicated intertextuality of 14th-century ridderromans is now more understood as part of a literary game of recognition and surprise between creators and recipients. However, little comparative research has been done into the exact nature of such reworking strategies and the ‘game of romance’ in a larger 14th-century corpus. This research projects asks how adaptation as a compositional process is positioned with regards to the poetics of the 14th-century ridderroman. This will be done through an intra-textual analysis of the poetical markers and through a thorough review of the material, performance and socio-cultural contexts of the corpus texts. As such, it also reconceptualizes the corpus of 14th-century ridderromans in terms of 14th-century material production and reception, rather than purely textual composition.

In 1973 verscheen de Belgisch-Nederlandse coproductie Het Dwaallicht in de bioscopen, een verfilming van Willem Elsschots gelijknamige novelle uit 1946. Het had echter niet veel gescheeld of regisseur Frans Buyens had een volledig andere film gerealiseerd. Oorspronkelijk had Buyens van de ministeriële filmcommissie immers een positief subsidiëringsadvies gekregen voor Top-Hit Girl, een satirische film over de communautaire verhoudingen in België. Maar voor het eerst sinds het ontstaan van het subsidiestelsel weigerde de christendemocratische minister van Cultuur, Frans van Mechelen, een filmproject te honoreren dat van de filmcommissie een positief advies had gekregen. In plaats daarvan gaf hij Buyens subsidies om Het Dwaallicht te verfilmen. Over de politiek en communautair geladen ontstaansgeschiedenis van Het Dwaallicht wisten we tot nog toe zo goed als niets. Deze bijdrage maakt dan ook de eerste nauwgezette analyse van de perikelen rond Top-Hit Girl en Het Dwaallicht. Dit gebeurt aan de hand van origineel archiefmateriaal, voornamelijk uit het archief van Frans Buyens in Amsab-ISG en het archief van het Fonds Film in Vlaanderen in het Rijksarchief te Beveren. De rol van politieke en Vlaams-ideologische factoren binnen de filmproductie en -verspreiding in het Vlaanderen van de jaren 1970 staat centraal. Tegelijk laat het artikel een nieuw licht schijnen op Buyens’ bijna mythische reputatie als eigenzinnige en compromisloze filmmaker.

Viviparity, a live-bearing mode of reproduction, has evolved over 100 times independently in vertebrate animals. Despite its frequent evolution, viviparity has a number of hypothesised disadvantages compared to the ancestral mode of reproduction, oviparity (egg-laying). One of these disadvantages is a reduction in locomotor performance during pregnancy, the period of internal development of the embryos. Adaptations to a live-bearing reproductive mode could have evolved to reduce these locomotor costs. In this thesis, I aim to find whether matrotrophy, post-fertilization nutrient provisioning (e.g. through a placental structure), and superfetation, the presence of multiple broods of different developmental stages, reduce the locomotor performance decline during pregnancy in the Poeciliidae, live-bearing fishes. In Chapter 2, we review the literature on the effects of pregnancy on morphology, performance and fitness. The biomechanics of each mode of locomotion (walking, swimming or flying) are distinct, and are affected differently by the added mass and volume of pregnancy. Furthermore, we list the possible adaptations that have evolved to reduce the locomotor costs of pregnancy, and divide them into three different categories: adaptations that reduce the locomotor costs of live-bearing, adaptations with which the locomotor costs of live-bearing are avoided, and adaptations to the life history of the animal. Lastly, we discuss hiatuses in the literature and experimental procedures to quantify the hypothesised benefit of adaptations. In Chapter 3, we compare the morphological changes during pregnancy in two closely-related species of live-bearing fish: Poeciliopsis turneri and Poeciliopsis gracilis. These species mainly differ in their mode of nutrient provisioning: P. gracilis is lecithotrophic and P. turneri is an extensive matrotroph. We tracked the morphological changes in 3D using a non-invasive method that creates three-dimensional body models. We find that P. turneri is more slender during the early stages of pregnancy, but increase in size more rapidly. This is in line with the locomotor costs hypothesis, which predicts that matrotrophic fish are more slender during the early stages of pregnancy, but that the difference between the body shapes of lecithotrophic and matrotrophic fish diminishes as pregnancy progresses. Our results indicate that matrotrophy could indeed provide a morphological advantage during pregnancy. Fast-start performance, a manoeuvre fish deploy to escape predatory strikes, is important for individual survival. In Chapter 4, we use state-of-the-art biomechanical methods to, for the first time, quantify this manoeuvre in three-dimensional space in adult fish (Heterandria formosa). We show that fish can orient their escapes in up- and downwards direction, and that this is correlated with a change in pitch angle of the body. Changes in roll angle of the body were not correlated with orientation of the fish. We furthermore demonstrate that stage 1 of the fast start, often described as a preparatory stage, can already contribute to propulsion. The results from Chapter 4 indicate that three-dimensional measurements of fast-start manoeuvres provide novel insights that were often overlooked. Measuring fast starts in three-dimensional space is relevant in determining the adverse effects of pregnancy on locomotor performance. We did this by comparing three species of live-bearing fish: P. turneri, H. formosa and Phalloptychus januarius. In Chapter 5, we show that pregnancy-induced changes in abdominal width are correlated with a reduction in performance in the horizontal plane (maximal horizontal speed, change in yaw angle), but less so in the vertical plane (maximal vertical speed, change in pitch angle). Furthermore, we demonstrate that an increase in abdominal width is correlated with a decrease in abdominal curvature and, for some species, in a decrease in maximal curvature rate in the abdomen. Lastly, we show that the pregnancy-induced morphological changes depend on the level of superfetation: species with a high level of superfetation experience higher frequency, but smaller amplitude changes in the shape of the abdomen. Whether superfetation actually results in a more slender body shape, as predicted by the locomotor costs hypothesis, depends on the level of reproductive investment. In this thesis, I show that pregnancy induces changes in morphology which comes with a cost in fast-start performance. Both matrotrophy and superfetation affect how body shape changes due to pregnancy, but whether the latter provides beneficial changes depends on the level of reproductive investment. Furthermore, I reveal that fast starts can have a substantial three-dimensional component which is relevant both to biomechanicists that aim to understand the physical and physiological mechanisms underlying this manoeuvre and to evolutionary biologists that strive to answer performance-related questions.

In his article "The Suppression of Satirizing Belgian Community Difficulties in Flemish Cinema and the Film Adaptation of Will-O'-the Wisp" Gertjan Willems analyzes two film projects of Frans Buyens. In 1970, Buyens received a positive funding recommendation for Top-Hit Girl, a satire about community difficulties in Belgium. However, Minister of Culture Frans van Mechelen refused to support the project because it conflicted with his pro-Flemish views. The minister successfully swept this controversial decision under the rug by offering Buyens the option to trade his socially critical project for a film adaptation of Willem Elsschot's novel Will-O'-the Wisp. This case study sheds new light on an understudied period in Belgian cinema and on the work of Frans Buyens. It demonstrates how the Flemish cinema landscape could be heavily influenced by political ideologies and interventions. Political maneuvers ensured that a satirical treatment of Belgian community difficulties in cinema was suppressed. Flemish cinema was instead directed towards adapting literary classics, thereby confirming the national culture instead of critically investigating it.

Many human and natural systems are highly complex, because they consist of many interacting parts. Such systems are known as complex adaptive systems (CAS). Understanding CAS is possible only by studying the interactions between constituent parts, rather than focussing only on the properties of the parts in isolation. Often, the possibilities for systematically studying these interactions in real-life systems are limited. Simulation models can then be an important tool for testing what properties may emerge, given various assumptions on the interactions in the system. Agent-based models (ABMs) are particularly useful for studying CAS, because ABMs explicitly model interactions between autonomous agents and their environment. Currently, the utility of ABMs is limited by a lack of available methodologies for analysing their results. The main tool for analysing CAS models is sensitivity analysis. Yet, standard methods of sensitivity analysis are not well-suited to deal with the complexity of ABMs. Thus, there is a need for sensitivity analysis methodologies that are specifically developed for analysing ABMs. The objective of this thesis is to contribute such methodologies. Specifically, we propose methodologies for (1) detecting tipping points, (2) analysing the effects of agent adaptation, and (3) analysing resilience of ABMs. Chapter 2 introduces traditional methods of sensitivity analysis. These methods are demonstrated by applying them to rank the most influential parameters of an ODE model of predator-prey interaction. Furthermore, the role of sensitivity analysis in model validation is discussed. In Chapter 3 we investigate the use of sensitivity analysis for detecting tipping points. Whereas bifurcation analysis methods are available for detecting tipping points in ODE models, these methods are not applicable to ABMs. Therefore, we use an ODE model to verify the results from sensitivity analysis against those of bifurcation analysis. We conclude that one-factor-at-a-time sensitivity analysis (OFAT) is a helpful method for detecting tipping points. However, OFAT is a local method that considers only changes in individual parameters. It is therefore recommended to supplement OFAT with a global method to investigate interaction effects. For this purpose, we recommend all-but-one-at-a-time sensitivity analysis (ABOS) as a graphical sensitivity analysis method that takes into account parameter interactions and can help with the detection of tipping points. In Chapter 4 we introduce a basic ABM model of agents competing in a spatial environment for a renewable resource. This basic model will be extended in the subsequent chapters, and will serve as a testing case for various sensitivity analysis methods. In Chapter 4, it is used to assess the utility of existing sensitivity analysis methods for ABMs. The results show that traditional methods of sensitivity are not sufficient to analyse the ABM, due to the presence of tipping points and other strong non-linearities in the model output. In contrast, OFAT is found to be helpful for detecting tipping points, as was suggested in Chapter 3. Based on these outcomes, OFAT is recommended as a starting point for sensitivity analysis of ABMs, preferably supplemented by a global method to investigate interaction effects. In Chapter 5 we extend the ABM of Chapter 4 by adding agent adaptation in the form of a mechanism of natural selection. On short time-scales, the model behaviour appears to be similar to the non-adaptive model version. On longer time-scales, the agent adaptation causes the state of the model to gradually change as agents continue to adapt to their surroundings. We propose a sensitivity analysis method to measure the effects of this adaptation. This method is based on a quantification of the difference between probability density functions of model version with and without adaptation. Using this method, we show that this adaptation increases the resilience of the system by giving it the flexibility needed to respond to pressures. In Chapter 6 we further extend the test-case by giving agents the option to harvest either cooperatively or individually. Cooperation increases the potential yields, but introduces the risk of defection of the interaction partner. It is shown that ecological factors, which are usually not considered in models on cooperation, strongly affect the level of cooperation in the system. For example, low levels of cooperation lead to a decreased population size, and causes the formation of small groups of agents with a higher level of cooperation. As a result, cooperation persists even without any mechanisms to promote it. Nevertheless, the inclusion of such mechanisms in the form of indirect reciprocity does further increase the level of cooperation. Furthermore, we show that the resulting high levels of cooperation, depending on the circumstances, can increase the resilience of the agent population against shocks. To conclude, in this thesis several methodologies have been proposed to help with ABM analysis. Specifically, OFAT and ABOS are recommended for detecting tipping points in ABMs, and in Chapter 5 a protocol is introduced for quantifying the effects of adaptation. By suggesting these methodologies, this thesis aims to contribute to the utility of ABMs, especially for studying CAS.

Blog op de website van de Hanzehogeschool waar ingegaan wordt op het project Adaptive Computational Thinking (ACT). Dit project is één van de vijf innovatieve onderwijsexperimenten die dit jaar gehonoreerd zijn binnen de SURF Innovation Challenge.

Toediening van lage doses nitriet veroorzaakte bij ratten hypertrofie van de zona glomerulosa van de bijnieren. Het mechanisme achter het ontstaan van deze hypertrofie was onduidelijk. Er is gesuggereerd dat deze hypertrofie het gevolg was van het bloeddrukverlagend effect van nitriet en de daarmee gepaarde activatie van het renine-angiotensine systeem. Daarom werd het effect van gelijktijdige blootstelling gedurende 4 weken aan nitriet en een remmer van het angiotensine converting enzym (ramipril, 1 mg/kg lichaamsgewicht/dag) op de morfologie van de bijnier onderzocht. Bloeddruk en hartslag werden continu geregistreerd. De plasma renine activiteit (PRA) en de concentraties van angiotensine I (AI) en aldosteron in plasma werden bepaald vlak voor en twee weken na begin van de blootstelling aan nitriet en ramipril. Blootstelling van de ratten aan ramipril veroorzaakte een permanente daling van de bloeddruk en ophoping van AI. Blootstelling aan nitriet leidde tot herhaalde, kortdurende perioden van licht verlaagde bloeddruk en een kleine stijging van de concentraties PRA en AI in plasma. Gelijktijdige blootstelling aan ramipril en nitriet leidde tot de hoogste AI concentratie hetgeen suggereerde dat het effekt van beide stoffen additief was. De aldosteron-concentratiebepaling liet geen statistisch significante verschillen tussen de groepen zien. De resultaten van de histopathologische beoordeling van de bijnieren en van de morfometrie lieten duidelijk zien dat ramipril de hypertrofie onder invloed van nitriet van de zona glomerulosa van de bijnieren onderdrukte. Deze hypertrofie was dus niet het gevolg van een direkt effect van nitriet op de bijnieren maar werd gemedieerd door het renine-angiotensine systeem dat was geactiveerd door de bloeddrukdaling als gevolg van nitriet. De hypertrofie - onder invloed van nitriet - van de zona glomerulosa van de bijnieren kan worden beschouwd als een normale fysiologische aanpassing aan herhaalde perioden van lichte bloeddrukdaling

Anthropogenic and climate-related stressors challenge the health of nearly every part of the global oceans. They affect the capacity of oceans to regulate global weather and climate, as well as ocean productivity and food services, and result in the loss or degradation of marine habitats and biodiversity. Moreover, they have a negative impact on maritime economic sectors and on the social welfare of dependent coastal populations. In order to overcome the deficiencies of traditional single-sector management, in the recent decades several scientific approaches emerged, based on the view of marine systems as Complex Adaptive Systems (CAS), i.e. systems where components interact in non-linear, path dependent ways, with lock-in and feedback loop mechanisms, and unpredictable effects also across scales. These approaches have been introduced into the texts of several international agreements related to marine CAS, and related management practices, with contrasting results in relation to effectiveness and integration of governance. This thesis evaluates for the first time the current international and European legal frameworks from the perspective of marine CAS. To accomplish this objective, four research objectives are formulated: (1) Develop a framework for marine CAS assessment and management; (2) Evaluate the entire European Union (EU) legal framework against the framework developed; (3) Evaluate the international legal framework for the assessment and management of the global oceans against the framework developed; and (4) Evaluate the implementation of the EU and global legal frameworks into practice. Chapter 2 develops a framework for marine CAS, based on the combination of two promising theoretical approaches: Adaptive Management (AM) and Transition Management (TM). The framework is based on the idea that AM and TM have the potential to overcome each other’s limitations, which are related to the insufficient attention to micro-level socio-economic components, and to the limited incorporation of environmental aspects into socio-technical assessments, respectively. More into detail, the proposed framework is articulated into three components. First, the two sets of marine social-ecological systems and connected socio-technical systems (e.g. fisheries, maritime transportation, coastal tourism and energy) must be clearly identified, and the complex interactions and influences between socio-economic patterns of production and consumption, and ecological components must be assessed. Second, the achievement of ecological resilience of a marine social-ecological system should be performed in coordination with transitions of unsustainable connected socio-technical systems. This implies that sustainability should be evaluated in relation to the pressures socio-technical systems generate on the ecological resilience of connected social-ecological systems, and related impacts. Third, the implementation of the two approaches should be articulated into iterative, learning- and science-based policy cycles, with mechanisms to foster coordination between the policy cycles of social-ecological and socio-technical systems. The benefits of this framework are threefold. First, the assessment of the two sets of social-ecological and socio-technical systems, taken together, allows to overcome current AM limitations and include micro-level socio-economic components into the assessment of ecological resilience. Second, by linking AM managers with established transition arenas, it is possible to overcome TM limitations and streamline the consideration of ecological aspects into the TM process. Third, by linking AM and TM policy cycles, it is possible to reduce the current legal and policy fragmentation. Chapters 3 and 4 apply the framework proposed in Chapter 2 to evaluate the EU and global legal frameworks for the assessment and management of marine CAS. Chapter 3 presents the first comprehensive review ever realised of the entire EU legal framework, composed of more than 12,000 EU legal acts, from the perspective of marine CAS assessment and management. It concludes that the EU legislation does not provide a fully coherent framework for the assessment and management of EU marine CAS. Although the Marine Strategy Framework Directive (MSFD; 2008/56/EC) is a major step towards this purpose, the present research highlights three major limitations: (1) the limited capacity of the MSFD to support the coordination between Member States sharing the same marine region or sub-region; (2) the insufficient characterisation of marine ecological resilience, in particular in relation to socio-economic elements, ecosystem services, human benefits and cross-scale interactions; and (3) the limited capacity of the MSFD to tackle the fragmentation of the EU legal framework and integrate ecological resilience into the objectives of sector-based laws and policies. Chapter 4 reviews 500 multilateral agreements, evaluated for the first time from the perspective of marine CAS. It shows that there is no international agreement aiming at the ecological resilience of the global oceans social-ecological system. Instead, the international legal framework is fragmented along two dimensions. On the one side, global agreements focus on specific objectives for determined socio-economic activities, ecological features or anthropogenic pressures. On the other side, regional agreements are in place for 18 ocean regions of the world, with a varying level of inclusion of elements of marine CAS assessment and management. The need is highlighted for a reformed global ocean governance framework, which should be based on a bio-geographical approach to the ecological resilience of the global oceans, and build on iteration, learning, and science-based advice to policy and management. Chapter 5 evaluates the implementation of the EU and global legal frameworks into the practice of assessment and management of a case-study area, the Adriatic Sea. It shows the importance of the MSFD as the first policy trying to deliver a CAS approach to marine assessment and management. However, the case-study investigation confirms the three limitations of the MSFD, laying in: 1) an insufficient geographical approach, where implementation is driven at national level and the requirement of cross-border cooperation is weak; 2) the vagueness of legal requirements, and the limited capacity to include socio-economic aspects into the required assessment; and 3) an insufficient capacity to coordinate with other laws, policies and programmes at various levels of governance. Based on the identified limitations, suggestions are advanced on how to strengthen the implementation of the MSFD, both at Adriatic and EU level. These suggestions are further advanced in Chapter 6, which includes detailed proposals on how to foster integrated large-scale marine monitoring in the EU, in order to contribute to the implementation of the MSFD in an efficient and effective way, also in relation to costs. Chapter 7 synthesizes the major findings of this thesis and evaluates the capacity of the framework to deliver a CAS approach to marine systems. It concludes that AM and TM, although holding different visions on sustainability and referring to different principles, have the potential to be put in synergy at the practical level. Further scientific research and management practices should focus on the need for AM and TM to overcome the relative isolation and foster synergies across sector-based management, in order to integrate environmental considerations into economic sectors. Suggestions are advanced to improve legal frameworks and policy practices at the global and EU level. They focus on the need: (i) to fill the gaps in the geographical scope of legal texts and to foster international cooperation at the right social-ecological scale; (ii) to increase guidance in translating complex scientific requirements into clear management objectives, and improve related data collection and sharing; and (iii) to reduce current legal and policy fragmentation through targeted, ecological resilience-based marine environmental impact assessments and maritime spatial planning. Lines for further scientific research are suggested, focusing on: (i) improving the evidence-base through additional case-studies; (ii) analysing legal frameworks and governance regimes in place for other marine social-ecological systems, like e.g. the United States of America, Canada, Australia and China; (iii) improving existing tools, or creating new ones for marine ecological resilience assessment; and (iv) developing innovative instruments and mechanisms to strengthen global oceans governance.

This thesis examines the three-way interaction between yeast-like symbionts, an insect herbivore [Nilaparvata lugens (Stål)] and its rice (Oryza sativa L.) host, during adaptation of the herbivore to resistant rice varieties. A long-term selection study (20 generations of continuous rearing, ca. 24 months) was conducted with N. lugens populations on four rice varieties (IR22, a susceptible variety and IR65482, IR62, and PTB33, three resistant varieties). Planthopper performance and the abundance of yeast-like symbionts (YLS) were monitored throughout the selection process. N. lugens populations adapted to the resistant varieties as noted by increasing body size and increased egglaying. Xylem feeding was observed as a possible behavioural adaptation of N. lugens: planthoppers on resistant plants had relatively high levels of xylem feeding compared with planthoppers on susceptible plants. Planthoppers selected on resistant varieties, had clear differences in YLS densities that were not related to fitness on the varieties and, therefore, did not support a YLS density-mediated adaptation hypothesis. Furthermore, this study examined whether YLS density affected the capacity of planthoppers to switch between hosts on which they have been selected for several generations (natal plant) to new varieties (exposed plants) under normal YLS densities (symbiotic) and after reduction of YLS densities by heat treatment (aposymbiotic). The results suggested that YLS do not mediate host plant switching in planthoppers as removal of symbionts influenced body weight but not the relative capacity of nymphs to feed on different plants. This study also tested if virulence is acquired by shared feeding sites with virulent and avirulent planthoppers. In the study, planthoppers with varying levels of virulence affected the host plants differently: The most virulent hoppers appeared to suppress rice defences to a greater extent than non-virulent planthoppers. Planthoppers attained highest weights on those plants on which virulent planthoppers had previously fed which suggests that feeding by the virulent planthoppers facilitated subsequent planthopper feeding on the same plant. Our preliminary results indicate that feeding by mixed virulent-avirulent populations could potentially accelerate adaptation by N. lugens to resistant rice varieties. The capacity of virulent and avirulent planthoppers to feed on a range of 24 resistant rice varieties was examined using a series of bioassays. Planthoppers were observed to feed and lay eggs on all the varieties tested, many of which have never been widely deployed in the field. Furthermore, planthoppers selected on resistant varieties often had increased fitness on other resistant varieties, even when these possess different resistance genes. However, there was no strong evidence that once planthoppers have adapted to a resistant variety, they will exhibit fitness costs on other varieties with dissimilar genes. The mechanisms underlying insect virulence are complex and further research on planthopper adaptation is necessary to help conserve genetic resources and prolong the durability of available resistant varieties.

Southern Africa is characterized by natural climate variability onto which human-induced climate change is being superimposed. Rural communities that depend heavily on rain-fed agriculture for their livelihood are particularly vulnerable to the effects of climate-related change. This report takes stock of existing perceptions of- and responses to climate change among smallholder farmers in the region, in the hope of contributing to a better understanding of the complexities of local knowledge- and adaptation systems.

SummaryAquatic photosynthetic organisms unavoidably experience light fluctuations that vary in amplitude, duration and origin, compromising their photosynthetic efficiency. Weather conditions and underwater flow cause continuous changes in irradiance to which the organisms have to adapt. Many light-adaptation strategies of photosynthetic organisms, such as light acclimation, photoprotection and state transitions are still not well understood. In this thesis, time-resolved fluorescence spectroscopy is used to obtain insight into the response of diatoms and cyanobacteria, both aquatic photosynthetic organisms, to changing light conditions.In chapter 2, photoacclimation (long-term acclimation to irradiance conditions) of the diatom Cyclotella meneghiniana is discussed. It is shown that the diatom cells fine-tune the amount of absorbed light energy by modifying their antenna size: cells grown in high light intensity have smaller antennas than those grown in low light. At the same time, the increase of growth light intensity leads to a decrease of the relative amount of photosystem I (PSI) as compared to PSII. Such a strategy might be beneficial for diatoms, since they are known to have an electron transfer cycle around PS II to release excess electrons produced in high light intensities. Besides discussing photoacclimation, we give a detailed description the fluorescence kinetics in C. meneghiniana. It is concluded that the diatom antenna, represented by light-harvesting fucoxanthin chlorophyll proteins (FCPs), transfer their excitation energy predominantly to PSII. FCPs associated with PSII are slightly richer in red-absorbing fucoxanthin than the FCPs associated with PSI, suggesting that PSII antennas (partly) constitute the antenna form FCPb (i.e. oligomeric antenna complexes).In chapter 3 the process of non-photochemical quenching (NPQ, thermal dissipation of excess absorbed light energy) of chlorophyll a fluorescence was studied in the same diatom species. Diatoms can rapidly switch on/off NPQ to respond to fast light-intensity changes in moving waters. They are capable to induce higher NPQ values than plants or other photosynthetic organisms. The reason for such high NPQ values, however, is not clear. We performed picosecond fluorescence measurements at 77K on cells locked in three different states: Besides using conventional unquenched and quenched states of the cells (in the absence and presence of the total NPQ component, respectively), we also performed measurements on the dark-adapted state directly following NPQ. In this state, diatoxantin (Dtx, a carotenoid related to NPQ), accumulated during the NPQ period and Dtx-related NPQ persists, while ΔpH-related NPQ has relaxed. In this way we revealed the following sequence of events during full development of NPQ. First, the pH gradient across the thylakoid membrane induces quenching of FCP trimers (FCPa complexes), while they are still part of PSII. This is followed by (partial) detachment of FCPa from PSII after which quenching persists. The pH gradient also causes the formation of Dtx, which leads to further quenching of isolated PSII cores and some aggregated FCPa. To summarize, quenching of PSII -both cores and complexes- and FCPa substantially contribute to NPQ in diatoms. The FCPb antenna form on the other hand does not contribute to the NPQ process.Certain aquatic photosynthetic organisms, such as cyanobacteria and green algae, can also cope with changing light conditions by dynamically varying the relative antenna size of PSI and of PSII. Consequently, a redistribution of light energy between the PSs is achieved. This phenomenon is called “state transitions”. It is known to be driven via a change in the redox status of electron carriers between PSII and PSI. In cyanobacteria, this redox change can be achieved via dark-light transitions. However, the cascade of microscopic events that lead to subsequent energy redistribution in cyanobacteria is still not completely clear. In chapter 4, a study on dark-light transitions using the cyanobacterium Synechocystis sp. PCC 6803 as a model organism is described. It is demonstrated that during dark to light transitions, there is mainly detachment of phycobilisomes (PBSs) (cyanobacterial antennas) from PSI, generally not followed by their attachment to PSII: only 15 % of the PBSs that detach from PSI actually move to PSII, while the major part remains detached from both PSs. We conclude that PSI-PSII-PBS megacomplexes, which were recently isolated using chemical cross-linking, are not involved in dark/light state transitions, suggesting that, if present, they are only transiently formed in cyanobacteria. To summarize, the findings presented in chapter 4 suggest that in cyanobacteria, unlike in green algae or higher plants, the main role of state transitions is to change the absorption cross-section of PSI, rather than that of PSII.In chapter 5, a study of the role of flv4-2 operon-encoded proteins in Synechocystis is described. Three genes are found in the operon: Flv4, Sll0218, and Flv2. Only recently flv4-2 operon-encoded proteins were found to constitute an additional photoprotective mechanism in a number of cyanobacteria by safeguarding PSII activity via an alternative electron chain. Its contribution becomes vital for the cells in high light and in air-level CO2, when the photosynthetic electron transport chain is over-reduced. It is demonstrated that deletion of the operon induces 20% PBS detachment. The reduced PSII dimer to monomer ratio, as a result of the absence of the small Sll0218 protein, favors a relative decrease of the PSII dimer content of about 20%, showing a direct correlation between PSII dimer destabilization and PBS detachment from reaction centers. On the other hand, the suggested binding of the Flv2/Flv4 heterodimer closely to the quinone B (QB) pocket in PSII increases the QB redox potential, thereby promoting forward electron transfer and increasing the charge separation rates in PSII. This activity of the Flv2/Flv4 heterodimer in combination with its earlier reported role as an electron acceptor in alternative electron chain provides more oxidized state of the PQ pool in high light and in air-level CO2.

Short Summary Cynthia McDougall--PhD Dissertation Knowledge, Technology, &Innovation Chairgroup (WASS) Adaptive collaborative governance of Nepal’s community forests: Shifting power, strengthening livelihoods Community-based natural resource governance has taken root around the globe. And, yet, as demonstrated by community forestry in Nepal, such programmes have generally not yet lived up to their goals and expectations. After decades of implementation, community forestry in Nepal faces several key challenges. Central to these challenges are: the need to increase equity in community forest user group decision making and benefit sharing; and, to increase the livelihood benefits from community forestry overall. The research project on which this study is based sought to address these challenges at the community forest user group scale. The research objective was to contribute empirically-based insights regarding if and how adaptive collaborative governance of community forests in Nepal can constructively influence engagement, livelihoods, social capital and conflict—especially in regard to women and the poor. Further, the research aimed to elucidate the underlying issue of power in community-based natural resource governance. In particular, it sought to contribute deeper, theoretically-based understanding of the persistence of power imbalances in community forestry, and of the potential of adaptive collaborative governance to shift such imbalances.

SummaryAquatic photosynthetic organisms unavoidably experience light fluctuations that vary in amplitude, duration and origin, compromising their photosynthetic efficiency. Weather conditions and underwater flow cause continuous changes in irradiance to which the organisms have to adapt. Many light-adaptation strategies of photosynthetic organisms, such as light acclimation, photoprotection and state transitions are still not well understood. In this thesis, time-resolved fluorescence spectroscopy is used to obtain insight into the response of diatoms and cyanobacteria, both aquatic photosynthetic organisms, to changing light conditions.In chapter 2, photoacclimation (long-term acclimation to irradiance conditions) of the diatom Cyclotella meneghiniana is discussed. It is shown that the diatom cells fine-tune the amount of absorbed light energy by modifying their antenna size: cells grown in high light intensity have smaller antennas than those grown in low light. At the same time, the increase of growth light intensity leads to a decrease of the relative amount of photosystem I (PSI) as compared to PSII. Such a strategy might be beneficial for diatoms, since they are known to have an electron transfer cycle around PS II to release excess electrons produced in high light intensities. Besides discussing photoacclimation, we give a detailed description the fluorescence kinetics in C. meneghiniana. It is concluded that the diatom antenna, represented by light-harvesting fucoxanthin chlorophyll proteins (FCPs), transfer their excitation energy predominantly to PSII. FCPs associated with PSII are slightly richer in red-absorbing fucoxanthin than the FCPs associated with PSI, suggesting that PSII antennas (partly) constitute the antenna form FCPb (i.e. oligomeric antenna complexes).In chapter 3 the process of non-photochemical quenching (NPQ, thermal dissipation of excess absorbed light energy) of chlorophyll a fluorescence was studied in the same diatom species. Diatoms can rapidly switch on/off NPQ to respond to fast light-intensity changes in moving waters. They are capable to induce higher NPQ values than plants or other photosynthetic organisms. The reason for such high NPQ values, however, is not clear. We performed picosecond fluorescence measurements at 77K on cells locked in three different states: Besides using conventional unquenched and quenched states of the cells (in the absence and presence of the total NPQ component, respectively), we also performed measurements on the dark-adapted state directly following NPQ. In this state, diatoxantin (Dtx, a carotenoid related to NPQ), accumulated during the NPQ period and Dtx-related NPQ persists, while ΔpH-related NPQ has relaxed. In this way we revealed the following sequence of events during full development of NPQ. First, the pH gradient across the thylakoid membrane induces quenching of FCP trimers (FCPa complexes), while they are still part of PSII. This is followed by (partial) detachment of FCPa from PSII after which quenching persists. The pH gradient also causes the formation of Dtx, which leads to further quenching of isolated PSII cores and some aggregated FCPa. To summarize, quenching of PSII -both cores and complexes- and FCPa substantially contribute to NPQ in diatoms. The FCPb antenna form on the other hand does not contribute to the NPQ process.Certain aquatic photosynthetic organisms, such as cyanobacteria and green algae, can also cope with changing light conditions by dynamically varying the relative antenna size of PSI and of PSII. Consequently, a redistribution of light energy between the PSs is achieved. This phenomenon is called “state transitions”. It is known to be driven via a change in the redox status of electron carriers between PSII and PSI. In cyanobacteria, this redox change can be achieved via dark-light transitions. However, the cascade of microscopic events that lead to subsequent energy redistribution in cyanobacteria is still not completely clear. In chapter 4, a study on dark-light transitions using the cyanobacterium Synechocystis sp. PCC 6803 as a model organism is described. It is demonstrated that during dark to light transitions, there is mainly detachment of phycobilisomes (PBSs) (cyanobacterial antennas) from PSI, generally not followed by their attachment to PSII: only 15 % of the PBSs that detach from PSI actually move to PSII, while the major part remains detached from both PSs. We conclude that PSI-PSII-PBS megacomplexes, which were recently isolated using chemical cross-linking, are not involved in dark/light state transitions, suggesting that, if present, they are only transiently formed in cyanobacteria. To summarize, the findings presented in chapter 4 suggest that in cyanobacteria, unlike in green algae or higher plants, the main role of state transitions is to change the absorption cross-section of PSI, rather than that of PSII.In chapter 5, a study of the role of flv4-2 operon-encoded proteins in Synechocystis is described. Three genes are found in the operon: Flv4, Sll0218, and Flv2. Only recently flv4-2 operon-encoded proteins were found to constitute an additional photoprotective mechanism in a number of cyanobacteria by safeguarding PSII activity via an alternative electron chain. Its contribution becomes vital for the cells in high light and in air-level CO2, when the photosynthetic electron transport chain is over-reduced. It is demonstrated that deletion of the operon induces 20% PBS detachment. The reduced PSII dimer to monomer ratio, as a result of the absence of the small Sll0218 protein, favors a relative decrease of the PSII dimer content of about 20%, showing a direct correlation between PSII dimer destabilization and PBS detachment from reaction centers. On the other hand, the suggested binding of the Flv2/Flv4 heterodimer closely to the quinone B (QB) pocket in PSII increases the QB redox potential, thereby promoting forward electron transfer and increasing the charge separation rates in PSII. This activity of the Flv2/Flv4 heterodimer in combination with its earlier reported role as an electron acceptor in alternative electron chain provides more oxidized state of the PQ pool in high light and in air-level CO2.

Southern Africa is characterized by natural climate variability onto which human-induced climate change is being superimposed. Rural communities that depend heavily on rain-fed agriculture for their livelihood are particularly vulnerable to the effects of climate-related change. This report takes stock of existing perceptions of- and responses to climate change among smallholder farmers in the region, in the hope of contributing to a better understanding of the complexities of local knowledge- and adaptation systems.

This thesis examines the three-way interaction between yeast-like symbionts, an insect herbivore [Nilaparvata lugens (Stål)] and its rice (Oryza sativa L.) host, during adaptation of the herbivore to resistant rice varieties. A long-term selection study (20 generations of continuous rearing, ca. 24 months) was conducted with N. lugens populations on four rice varieties (IR22, a susceptible variety and IR65482, IR62, and PTB33, three resistant varieties). Planthopper performance and the abundance of yeast-like symbionts (YLS) were monitored throughout the selection process. N. lugens populations adapted to the resistant varieties as noted by increasing body size and increased egglaying. Xylem feeding was observed as a possible behavioural adaptation of N. lugens: planthoppers on resistant plants had relatively high levels of xylem feeding compared with planthoppers on susceptible plants. Planthoppers selected on resistant varieties, had clear differences in YLS densities that were not related to fitness on the varieties and, therefore, did not support a YLS density-mediated adaptation hypothesis. Furthermore, this study examined whether YLS density affected the capacity of planthoppers to switch between hosts on which they have been selected for several generations (natal plant) to new varieties (exposed plants) under normal YLS densities (symbiotic) and after reduction of YLS densities by heat treatment (aposymbiotic). The results suggested that YLS do not mediate host plant switching in planthoppers as removal of symbionts influenced body weight but not the relative capacity of nymphs to feed on different plants. This study also tested if virulence is acquired by shared feeding sites with virulent and avirulent planthoppers. In the study, planthoppers with varying levels of virulence affected the host plants differently: The most virulent hoppers appeared to suppress rice defences to a greater extent than non-virulent planthoppers. Planthoppers attained highest weights on those plants on which virulent planthoppers had previously fed which suggests that feeding by the virulent planthoppers facilitated subsequent planthopper feeding on the same plant. Our preliminary results indicate that feeding by mixed virulent-avirulent populations could potentially accelerate adaptation by N. lugens to resistant rice varieties. The capacity of virulent and avirulent planthoppers to feed on a range of 24 resistant rice varieties was examined using a series of bioassays. Planthoppers were observed to feed and lay eggs on all the varieties tested, many of which have never been widely deployed in the field. Furthermore, planthoppers selected on resistant varieties often had increased fitness on other resistant varieties, even when these possess different resistance genes. However, there was no strong evidence that once planthoppers have adapted to a resistant variety, they will exhibit fitness costs on other varieties with dissimilar genes. The mechanisms underlying insect virulence are complex and further research on planthopper adaptation is necessary to help conserve genetic resources and prolong the durability of available resistant varieties.

Short Summary Cynthia McDougall--PhD Dissertation Knowledge, Technology, &Innovation Chairgroup (WASS) Adaptive collaborative governance of Nepal’s community forests: Shifting power, strengthening livelihoods Community-based natural resource governance has taken root around the globe. And, yet, as demonstrated by community forestry in Nepal, such programmes have generally not yet lived up to their goals and expectations. After decades of implementation, community forestry in Nepal faces several key challenges. Central to these challenges are: the need to increase equity in community forest user group decision making and benefit sharing; and, to increase the livelihood benefits from community forestry overall. The research project on which this study is based sought to address these challenges at the community forest user group scale. The research objective was to contribute empirically-based insights regarding if and how adaptive collaborative governance of community forests in Nepal can constructively influence engagement, livelihoods, social capital and conflict—especially in regard to women and the poor. Further, the research aimed to elucidate the underlying issue of power in community-based natural resource governance. In particular, it sought to contribute deeper, theoretically-based understanding of the persistence of power imbalances in community forestry, and of the potential of adaptive collaborative governance to shift such imbalances.

Terwijl inspanningen worden geleverd om via natuurbeheer potentieel geschikte groeiplaatsen te herstellen, is het onzeker of specifieke doelsoorten deze herstelde gebieden spontaan kunnen bereiken. De manier waarop plantensoorten hun zaden verbreiden, is dan ook cruciaal voor hun voortbestaan. Dit is zeker zo voor pionierssoorten zoals orchideeën, waarvan lokale populaties doorgaans een kort leven zijn beschoren. Dat orchideeën hun zaden over lange afstanden kunnen verbreiden staat vast, maar hoe groot zijn die afstanden juist? Komen die zaden ook terecht op de weinige geschikte groeiplaatsen? En zo ja, zullen de zaden ook effectief kiemen?

Rik Leemans (Wageningen Universiteit) reageert op het artikel van Kramer over de beuken, de te verwachten klimaatverandering en de gevolgen voor bossen en boomsoorten samen

Proteases from the digestive system of insects are targets of plant defense: the plant produces protease inhibitors to eliminate them. These protease inhibitors are small proteins, which can also be applied in crop protection, for instance through techniques of genetic modification (GMO). However, a number of polyphagous insects, for example Helicoverpa spp., appear not to be affected by protease inhibitors. Being polyphagous, these insects are used to the presence of different natural protease inhibitors in their diet. This may explain why they have adapted and use a protease that cannot be inhibited by a range of protease inhibitors. This protease is homologous to proteases that are extremely sensitive to inhibitors, and we are seeking a molecular understanding of how this adapted protease can avoid being inhibited. Protease inhibitors do work against a number of non-polyphagous insects and also against insects like aphids and thrips, which usually avoid contact with protease inhibitors. Application in agriculture is therefore increasing