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Commentary: Managing Recovery Resilience in Coral Reefs Against Climate-Induced Bleaching and Hurricanes: A 15 Year Case Study From Bonaire, Dutch Caribbean
Get PDFThe shifting position of homeowners in flood resilience: From recipients to key-stakeholders
Get PDFThe academic debate on flood risk governance is paying increased attention to the shifting position of homeowners. Homeowners are increasingly expected to adapt their homes to protect against possible floods. Although an overall agreement seems to exist on the involvement of homeowners in flood risk governance, the academic literature is dispersed in its argumentation on why homeowners should be involved. Therefore, this article provides a coherent overview of the transition from flood protection to flood risk management, and subsequently of the arguments that unfold regarding the shifting position of homeowners within this debate. This overview, based on a systematic review of the academic literature, helps to shed light on the changing role of homeowners in flood risk governance and contributes to categorizing the arguments used in current academic reasoning on homeowner involvement in flood risk governance. We use a conceptual distinction between macro-level and micro-level arguments, and between individual and collective efforts to structure our results. This conceptual overview illustrates the potential gap in convincing homeowners of the urgency to take action, because the connection between the macro-level arguments (i.e., climate change and responsibility) and the micro-level arguments (i.e., minimizing flood damage on privately owned properties) is generally not made. We, therefore, suggest that a stronger coherence in the argumentation would contribute to increase homeowner awareness of their changing responsibilities, which might bring about a future shift toward a new phase in flood risk governance, in which the responsibilities of homeowners are more explicitly acknowledged and integrated into climate adaptation strategies. This article is categorized under: Engineering Water > Planning Water Human Water > Water Governance.</p
Impact of Processing Factors on Quality of Frozen Vegetables and Fruits
Get PDFIn this paper I review the production of frozen vegetables and fruits from a chain perspective. I argue that the final quality of the frozen product still can be improved via (a) optimization of the complete existing production chain towards quality, and/or (b) introduction of some promising novel processing technology. For this optimization, knowledge is required how all processing steps impact the final quality. Hence, first I review physicochemical and biochemical processes underlying the final quality, such as water holding capacity, ice crystal growth and mechanical damage. Subsequently, I review how each individual processing step impacts the final quality via these fundamental physicochemical and biochemical processes. In this review of processing steps, I also review the potential of novel processing technologies. The results of our literature review are summarized via a causal network, linking processing steps, fundamental physicochemical and biochemical processes, and their correlation with final product quality. I conclude that there is room for optimization of the current production chains via matching processing times with time scales of the fundamental physicochemical and biochemical processes. Regarding novel processing technology, it is concluded in general that they are difficult to implement in the context of existing production chains. I do see the potential for novel processing technology combined with process intensification, incorporating the blanching pretreatment—but which involves quite a change of the production chain.</p
Cycles and interactions : A mathematician among biologists
Get PDFThe backbone of this thesis is the interdisciplinary interaction between dynamic systems theory and a selection of biological problems. Each chapter focuses in one problem, namely plankton dynamics, cell development paths and sleep-wake dynamics. Despite these topics may seem disconnected, they share an important feature: all of them show cyclic behaviour under certain circumstances. In the present thesis we show that cyclic (or chaotic) behaviour is deeply related with plankton biodiversity. We also use cycles to show, in an intuitive way, that Waddington’s epigenetic landscapes (a common visual tool in stem cell research) are poorly defined, and we provide a practical solution to this. Lastly, we provide an algorithm to forecast a transition between synchronized and non-synchronized cyclic systems (such as normal sleep – insomnia, or normal hearth functioning – arrhythmia), with potential applications in medical sciences
High-tech urban agriculture in Amsterdam: An actor network analysis
Get PDFThe agriculture and horticulture sector in the Netherlands is one of the most productive in the world. Although the sector is one of the most advanced and intense agricultural production systems worldwide, it faces challenges, such as climate change and environmental and social unsustainability of industrial production. To overcome these challenges, alternative food production initiatives have emerged, especially in large cities such as Amsterdam. Some initiatives involve producing food in the urban environment, supported by new technologies and practices, so-called high-tech urban agriculture (HTUA). These initiatives make cultivation of plants inside and on top of buildings possible and increase green spaces in urban areas. The emerging agricultural technologies are creating new business environments that are shape d by technology developers (e.g., suppliers of horticultural light emitting diodes (LED) and control environment systems) and developers of alternative food production practices (e.g., HTUA start-ups). However, research shows that the uptake of these technological innovations in urban planning processes is problematic. Therefore, this research analyzes the barriers that local government planners and HTUA developers are facing in the embedding of HTUA in urban planning processes, using the city of Amsterdam as a case study. This study draws on actor-network theory (ANT) to analyze the interactions between planners, technologies, technology developers and developers of alternative food production practices. Several concepts of ANT are integrated into a multi-level perspective on sustainability transitions (MLP) to create a new theoretical framework that can explain how interactions between technologies and planning actors transform the incumbent social-technical regime. The configuration of interactions between social and material entities in technology development and adoption processes in Amsterdam is analyzed through the lens of this theoretical framework. The data in this study were gathered by tracing actors and their connections by using ethnographic research methods. In the course of the integration of new technologies into urban planning practices, gaps between technologies, technology developers, and planning actors have been identified. The results of this study show a lacking connection between planning actors and technology developers, although planning actors do interact with developers of alternative food production practices. These interactions are influenced by agency of artefacts such as visualizations of the future projects. The paper concludes that for the utilization of emerging technologies for sustainability transition of cities, the existing gap between technology developers and planning actors needs to be bridged through the integration of technology development visions in urban agendas and planning processes.</p
Modelling food security : Bridging the gap between the micro and the macro scale
No full textAchieving food and nutrition security for all in a changing and globalized world remains a critical challenge of utmost importance. The development of solutions benefits from insights derived from modelling and simulating the complex interactions of the agri-food system, which range from global to household scales and transcend disciplinary boundaries. A wide range of models based on various methodologies (from food trade equilibrium to agent-based) seek to integrate direct and indirect drivers of change in land use, environment and socio-economic conditions at different scales. However, modelling such interaction poses fundamental challenges, especially for representing non-linear dynamics and adaptive behaviours. We identify key pieces of the fragmented landscape of food security modelling, and organize achievements and gaps into different contextual domains of food security (production, trade, and consumption) at different spatial scales. Building on in-depth reflection on three core issues of food security – volatility, technology, and transformation – we identify methodological challenges and promising strategies for advancement. We emphasize particular requirements related to the multifaceted and multiscale nature of food security. They include the explicit representation of transient dynamics to allow for path dependency and irreversible consequences, and of household heterogeneity to incorporate inequality issues. To illustrate ways forward we provide good practice examples using meta-modelling techniques, non-equilibrium approaches and behavioural-based modelling endeavours. We argue that further integration of different model types is required to better account for both multi-level agency and cross-scale feedbacks within the food system.</p
Temperature has a causal and plastic effect on timing of breeding in a small songbird
No full textPhenotypic plasticity is an important mechanism by which an individual can adapt its seasonal timing to predictable, short-term environmental changes by using predictive cues. Identification of these cues is crucial to forecast the response of species to long-term environmental change and to study their potential to adapt. Individual great tits (Parus major) start reproduction early under warmer conditions in the wild, but whether this effect is causal is not well known. We housed 36 pairs of great tits in climate-controlled aviaries and 40 pairs in outdoor aviaries, where they bred under artificial contrasting temperature treatments or in semi-natural conditions, respectively, for two consecutive years, using birds from lines selected for early and late egg laying. We thus obtained laying dates in two different thermal environments for each female. Females bred earlier under warmer conditions in climate-controlled aviaries, but not in outdoor aviaries. The latter was inconsistent with laying dates from our wild population. Further, early selection line females initiated egg laying consistently ∼9 days earlier than late selection line females in outdoor aviaries, but we found no difference in the degree of plasticity (i.e. the sensitivity to temperature) in laying date between selection lines. Because we found that temperature causally affects laying date, climate change will lead to earlier laying. This advancement is, however, unlikely to be sufficient, thereby leading to selection for earlier laying. Our results suggest that natural selection may lead to a change in mean phenotype, but not to a change in the sensitivity of laying dates to temperature.</p
The hydro-social dynamics of exclusion and water insecurity of Dalits in peri-urban Kathmandu Valley, Nepal: fluid yet unchanging
Get PDFProcesses of urbanisation create peri-urban spaces that are socially and institutionally fluid. In this article, we analyse how contestations and competition over declining water resources in peri-urban Kathmandu Valley in Nepal reshape water use, access and rights as well as user communities themselves, by creating and reproducing new and existing exclusions and solidarities. Traditional caste-based discriminatory practices, prohibiting Dalits from physically accessing water from sources used by higher castes, are said to be no longer practiced in Nepal. However, our findings show that, exclusion persists for Dalits even though the characteristics of exclusion have changed. In situations of competing water claims in the research location, Dalit households, unlike higher-caste groups, are unable to exercise prior-use water rights. Their water insecurity is compounded by their relative inability to mobilise political, social and economic resources to claim and access new water services and institutions. By juxtaposing the hydro-social and social exclusion analytical frameworks, we demonstrate how exclusions as well as interpretations and experiences of water (in)security are reified in post-Maoist, supposedly inclusive Nepa