63 research outputs found
BIODIVERSITY MANAGEMENT FOR INTEGRATING CONSERVATION AND PRODUCTION IN MODERN AGRICULTURAL SYSTEMS
No full textThe conservation of biodiversity is one of the primary concerns when dealing with agro-ecosystems, which other than providing food and fodder resources, can benefit of high levels of ecological functioning. The multifunctionality of agro-ecosystems has to be assessed in a multidisciplinary way and new methodologies should be developed to tackle it, at different spatial and temporal scales. The multi-scale approach is useful to delineate an overall view of the ecosystem and productive services of agricultural areas. This manuscript presents three researches dealing with the conservation of biodiversity, with a view to agricultural production, that were carried out in three different contexts of interest. Such a choice was intended to permit the application of new techniques and to adapt existing ones to different spatial and temporal scales.
The first context was chosen to delineate a new methodology for conserving semi-natural water resources in an highly fragmented landscape scenario, the district of Milan. In particular, one of the key elements of the territory is that of fontanili, semi-natural plain springs that represent both strong water resources for agriculture and the remnants of ancient green zones, but are more and more affected by urbanization rates and intensification of agricultural practices. They are listed as habitats for some endangered species, mainly aquatic, and conservation strategies are needed to preserve their ecosystem services. We chose to rely on landscape ecology analyses, which are able to assess how ecological corridors are structured between sources and sinks of biodiversity, represented by fontanili. We developed a new indicator, called Fuzzy Functionality Index (FFI), that for the first time collimates two of the more common types of analysis: the structural analysis of landscape fragmentation, and the assessment of species-specific permeability to movement. The index, resulting from a participative process, was at the basis of the spatial assessment of ecological corridors between fontanili and has proven to be highly effective and very flexible. It permits one to assemble geographic data, the knowledge of a multidisciplinary team and open source software to obtain a simple-to-read, mapped index at virtually no cost, eliding the issues of the traditional methods.
The second context is that of a rural livestock farming district at high altitudes, in the Alps of Northern Italy. Alpine meadows have been exposed to profound management shifts in modern times: changes in plant species composition and biodiversity losses are widespread issues. The aim of the work was to inspect how the variability of meadows could be explainable by the environment they depend on and by the management strategies applied. We analyzed the plant species composition, biodiversity and forage value of meadows in the context and their relationships with environmental and management variables, collected among the farmers. The management variables explained a small amount of variance: only the number of cuts per year remarkably explained the plant species composition and biodiversity. The number of cattle and the field applied nitrogen only described the most intensively managed communities. The environmental variables better described the variability of responses: in particular, an increase of the Landolt Nutrient Index was associated with an increase of the forage value opposite to a decrease of the Shannon Index. The negative correlation between the two responses highlights a known dilemma referring to high altitude meadow communities, which are subjected to important environmental constraints. Some taxa as Anthriscus sylvestris, Heracleum sphondylium, Rumex acetosa and Polygonum bistorta were found to critically unbalance the species composition thus the overall biodiversity. This is certainly the most critical finding, explainable by the late first cuts commonly adopted and by long-term intensive management choices. Homologated management strategies could not explain the wide ecological variability investigated, but indeed they made possible to understand how the system should be deeply revised, in respect to limiting environmental constraints and fodder capabilities at high altitudes.
The third context is that of an agronomic field experiment carried out over a long period. The work compares biomass, Milk Feed Units (MFU) and Crude Proteins (CP) yields, over a period of 21 years (1986-2006), referring to five fodder cropping systems: (i) a one-year double-crop rotation (R1) of autumn-sown Italian ryegrass + spring-sown silage maize; (ii) a three-year rotation (R3) of grain maize (first year), autumn-sown barley + silage maize (second year), and Italian ryegrass + silage maize (third year); (iii) a six-year rotation (R6) of Italian ryegrass + silage maize (years 1,2,3) + mixed meadow of white clover and tall fescue (years 4,5,6); (iv) a continuous grain maize (CM); and (v) a permanent meadow (PM). All cropping systems were subjected to two levels of agronomic inputs: high (A), indicating the amounts of fertilizers and herbicides normally applied by farmers in the region, and low (B) consisting in reduced amounts of fertilizers (-30%) and herbicide rates (-25%) compared to A. We found R1 > R3 > R6 > PM > CM in terms of biomass yields, with a slightly different trend for MFU yields, whereas R6 > R1 > PM > R3 > CM regarding CP yields. The two treatments always resulted A > B. The five cropping systems significantly varied between the 21 years of experiment: all of them showed decreasing performances except for PM, improving in biomass, MFU and CP over time. The three rotations (R1, R3, R6) appeared the most stable cropping systems over time. These findings suggest the importance of complex cropping systems, which could provide high quality of fodder besides guaranteeing a remarkable agricultural diversification
Meadows species composition, biodiversity and forage value in an Alpine district : Relationships with environmental and dairy farm management variables
No full textAlpine meadows have been exposed to relevant management shifts in the last decades, with changes in plant species composition and biodiversity losses often occurring in favor of augmented foraging capabilities, especially in marginal rural contexts. In this study, we analyzed the relationships among the plant species composition, biodiversity and forage value of meadows and two sets of variables, environmental and management ones, in a dairy district of the Central Italian Alps. Results indicate that management variables could only explain limited variability of the meadows under study: for instance, the number of cuts per year is available to justify the plant species composition and biodiversity of such coenoses. Moreover, the environmental variables better described the variability of responses, due to the harsh environmental constraints of the area under examination, located at high altitudes. The shared effects of the two sets explained larger variance than the management set alone, due to the complex relationships of environmental and management factors in the context. The forage value of meadows, an indicator of hay quality, was found negatively associated with the Shannon Index. This behavior highlights a known dilemma which especially refers to high altitude communities as the ones under study, clearly highlighting trade-offs between their production and biodiversity. Some taxa as Anthriscus sylvestris, Heracleum sphondylium and others critically unbalance the species composition of meadows, thus their overall biodiversity, at low altitudes. This finding, explainable by the late first cuttings commonly adopted by all farmers, suggests the eutrophication of coenoses. The management choices inspected did not reflect on the wide variability of meadows, but indeed they made possible to understand how this farming system should be deeply revised, with respect to environmental constraints and meadows’ fodder capabilities
Designing ecological corridors in a fragmented landscape: A fuzzy approach to circuit connectivity analysis
No full textLandscape connectivity analysis is a major tool in supporting biodiversity conservation. Several methodologies have been developed to tackle it by following two main paths. The first path exploits graph approaches and models focal nodes' connections on a resistance/conductance matrix depending on focal species' movement potential. The second path considers geometrical pattern analyses based on the calculation of structural landscape metrics. These approaches separately investigate functional and structural features of the landscape, and may come short of a total definition if used separately. Here we propose a new scalable, modular, participative and open-source procedure based on Fuzzy logic to combine the functional and structural aspects of connectivity. We applied this method on the highly fragmented landscape of the Po Plain, focusing on its rare and endangered plain springs named fontanili. We identified an expert panel and involved it in the assignation of permeability values of land use classes with respect to the capacity of movement of animal species typical of fontanili. We concurrently performed a quantitative evaluation of the landscape fragmentation with a moving window. We found that the functional and structural evaluations were poorly correlated in the area under study (Pearson's r = -0.35, p < 0.001). We thus integrated these two non-overlapping analyses of the landscape by Fuzzy logic using thresholds and combination weights obtained from questionnaires proposed to the expert panel. The resulting index, termed Fuzzy Functionality Index (FFI), improved the level of information associated with landscape classification. By merging functional and structural aspects of the landscape, the FFI allowed us to discriminate different functional values of equally permeable parcels and vice versa. We demonstrate that FFI may act as a conductance measure in a circuit theory approach, highlighting ecological corridors between focal points of species' distribution. We present FFI as an effective predictive index to inspect complex and non-linear landscape dynamics
The impact of an additional phenology model on the performance of conceptual hydrological models
No full textThis thesis investigates the impact of a phenology model on conceptual hydrologic model. In conventional conceptual hydrologic models the evapotranspiration is partitioned into evaporation and transpiration by a combination of the potential evaporation and the availability of water. This way the seasonal differences in vegetation dynamics are not taken into account. These vegetation dynamics represent the presence of transpiring leaves in summer, changing to an almost complete absence of transpiration in winter for some vegetation types. Including information on these vegetation dynamics could potentially improve the way streamflow and evaporation is modelled by conceptual hydrologic models. To investigate the impact of a phenology model on conceptual hydrologic models the FLEXmodel is adjusted with a phenology model based on the ’Kc-ETo’ approach of the Food and Agricultural Organisation (FAO) of the UN. With the conventional FLEX-model and the FAOadjusted FLEX-model, 28 catchments from the USA are simulated in terms of streamflow and transpiration. The 28 catchments differ in terms dominant vegetation type and climate indices. The conventional model and the adjusted model are calibrated with streamflow observations and transpiration data from NASA Global Land Data Assimilation System (GLDAS) both separately and together. The conventional FLEX-model and the FAO-adjusted FLEX-model are compared to each other in order to determine under what climate conditions and for which vegetation types the phenology adjustment improves the performance of the model in terms of the ability to simulate streamflow and transpiration and the predictive capacity of the model. The streamflow simulation of the FLEX-model does not improve by the FAO-adjustment. The FAO adjustment does cause an improvement in the mean seasonal sum of the discharge in the spring months, which is structurally underestimated by the conventional model due to an overestimation in spring of the transpiration caused by the lack of information on vegetation dynamics. However the transpiration simulation of the FLEX-model does improve drastically by the FAO-adjustment. The large overestimation of the transpiration in early spring by the conventional FLEX-model is solved by the FAO-adjustment, improving the NS- and NSlogefficiencies for all catchments, regardless of their vegetation type of climate conditions.Civil Engineerin
Modular Approach for the Optimal Wind Turbine Micro Siting Problem through CMA-ES Algorithm (abstract)
No full textAlthough, only in recent years, northern European countries started to install large offshore wind farms, it is expected that by 2020, several dozens of far and large offshore wind farms (FLOWFs) will be built. These FLOWFs will be constituted of a considerable amount of wind turbines (WTs) packed together, leading to an energy density increase. However, due to shadowing effects between WTs, power production is reduced, resulting in a revenues decrease. Therefore, when FLOWFs are considered, wake losses reduction is an important optimization goal. This work presents a modular approach to optimize the energy yield of FLOWFs through an evolutionary algorithm. The method consists of a modular strategy where the site wind rose information is used in different steps, which accelerates the calculation of the wake losses. The main contribution of this paper is the use of surrogate models to optimize the layout of offshore wind farms. Although, the surrogates models do not make use of the entire wind information set, they preserve the main problem trend. At the end, the results obtained are tested for their sensitivity regarding the wind data and the turbine locations.Electrical Sustainable EnergyElectrical Engineering, Mathematics and Computer Scienc
Operation of grid-connected DFIG under unbalanced grid voltage condition
No full textDoubly fed induction generator (DFIG) still shares a large part in today's wind power market. It provides the benefits of variable speed operation cost-effectively, and can control its active and reactive power independently. Crowbar protection is often adopted to protect the rotor-side voltage source converter (VSC) from transient overcurrent during grid voltage dip. But under unbalanced grid voltage condition, the severe problems are not the transient overcurrent, but the electric torque pulsation and dc voltage ripple in the back-to-back VSCs. This paper develops dynamic models in MATLAB/Simulink, validates it through experiments, investigates the behavior of DFIG during unbalanced grid voltage condition, and proposes new controllers in separated positive and negative sequence. Methods to separate positive and negative sequence components in real time are also developed, and their responses to unsymmetrical voltage dip are compared. Simulation results prove that the separated positive and negative sequence controllers limit the torque pulsation and dc voltage ripple effectively.Electrical Sustainable EnergyElectrical Engineering, Mathematics and Computer Scienc
Karl Haushofer en het Nationaal-Socialisme: tijd, werk en invloed
No full textFor some the nineteenth century was the age of prophets.
All over Europe new ideas struggled for precedence. Idealism was
a strong issue, but committing to particular political ideas had its
risks. Over the years ideas about country and nation had undergone
changes. Under the influence of Johann Gottfried Herder (1744-1803)
an organic concept of nations had become widely accepted. The assumption was that nations – like people, animals and plants – went
through the phases of birth, growth, prosperity and death. As a mere
metaphor, this concept was relatively harmless. However, Herder’s
organic ideas also seeped through to science. Due to Charles Darwin’s
influence such ideas found their way into political and scientific jargon and thought. Metaphor had turned into identity.1 Geography
became political geography and political geography engendered geopolitics.
Karl Haushofer was Germany’s main exponent of geopolitics. His
contemporaries, geo-politicians such as Richard Henning and Leo
Körholz defined the term geopolitics…”Geopolitics is a method of
political analysis which emphasizes the role played by geography in
international relations”. In his Dictionary of Geopolitics author John
O’Loughlin in 1994 concluded that Geopolitik was mainly a political
weapon, intellectual ammunition, from which evolved German expansionism and hegemony concepts
Control of DFIG under unsymmetrical voltage dip
No full textElectrical Engineering, Mathematics and Computer Scienc
Sustainability consult Irmão beach restaurant
No full textIrmão is a beach restaurant located in the region of Lisbon in Portugal and has been taken over by the new owners one year ago. Since the takeover, the owners of Irmão have been trying to work in a sustainable way, but there is always room for improvement. In addition, Irmão may have to move 100 metres inland due to a possible change in local regulations. Because of the uncertainty in the course of events, this report is written as guideline in order to make the current restaurant more sustainable and as a guideline during the design of the new beach restaurant, should the restaurant have to be relocated. The aim of the report is therefore to provide beach restaurant Irmão with a consult on how to establish and operate a more sustainable beach restaurant, in present or future times. The study, executed at Irmão, focused on three main themes; the water system, waste management and the energy system. The level of sustainability in these areas is quantified in three ways, namely: the use of resources such as fossil fuels and groundwater; the emission of greenhouse gases CO2, NOx and CH4; the pollution of the direct environment, for example waste that ends up in nature or polluted waste water that flows into the soil. The present and future times refer to the two different scenarios used to implement sustainable solutions. If the restaurant is allowed to stay at its current location, it is referred to as the Improved Irmão Scenario. If the location has to be changed, it is referred to as the Future Irmão Scenario. For the Improved Irmão Scenario, the boundaries and limits of the current restaurant are taken into account and the design is carried out within these limits. For the Future Irmão Scenario on the other hand, these limits are loosened and the design is carried out from scratch. To provide Irmão with a consult how to establish and operate a more sustainable beach restaurant, three steps were taken. First, the current situation of the three subjects is analysed to get a clear understanding of the current situation. This is done to have a baseline against which the final improvements can be compared. Secondly, different solutions to make Irmão more sustainable, within the three main topics, are compared using a multi¬criteria analysis to determine the most promising solutions. Thirdly, the final solutions are elaborated for the Improved Irmão Scenario and for the Future Irmão Scenario. Regarding the Water system, the analysis showed that the water consumed at Irmão partly originates from the water grid and partly from the borehole in the dunes. The water use is estimated to cause an emission of 182 kg CO2 annually, leaving little room for improvement in emission reduction as this is a relative low amount. However, the water system is currently not water-efficient because it does not contain any water circularity and the water system does not contain any water saving equipment. Improvements regarding water usage are therefore possible. Regarding waste management, the analysis showed that currently, only residual waste is not recycled. Therefore, the section on waste management focused on making residual waste more sustainable. Regarding the energy system of Irmão, it became clear from the analysis that Irmão currently consumes propane gas and electricity from the local electricity grid. Both the consumption of propane gas and electricity from the local grid contribute to an emission of 26.8 tonnes of CO2 annually. From all processes carried out during the operation of Irmão, only the consumption of propane gas leads to an emission of NOx, namely 382 kg NOx annually…Multidisciplinary Project: Mechanical Engineering | Multi-Machine Engineering, Civil Engineering | Hydraulic Engineering and Electrical Engineering | Sustainable Energy TechnologyMultidisciplinary ProjectCivil Engineering | Hydraulic EngineeringElectrical Engineering | Sustainable Energy TechnologyMechanical Engineering | Multi-Machine Engineerin
Discussiedossier over Clé Lesger, <i>Power and urban space in pre-modern Holland</i>
No full textIn 2024, Clé Lesger published his latest book titled Power and Urban Space in Pre-Modern Holland. Arenas of Appropriation in the Netherlands, 1500-1850. In this study he develops a new perspective on the question of power and inequality by showing how urban space was appropriated by different groups and how the unequal relations between them were expressed and reproduced in this process. As such, the book addresses the political economy of the early modern Dutch cities and asks why their inhabitants accepted the political and economic inequalities that characterisedthese urban societies. Because of its scope and originality, this book deserves a longer discussion in Stadsgeschiedenis. The editors have found three expert colleagues – Marjolein Schepers, Bob Pierik, and Maarten Prak – willing to write reflections on different aspects of Power and Urban Space, to which the author replies in the closing part
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