Compost uit natuur en landschap

Bij het beheer van natuurgebieden en landschapselementen zoals houtwallen, rietlanden en singels, komen grote hoeveelheden plantaardig materiaal vrij. Afvoer en verwerking van dit materiaal drukken zwaar op de beheerskosten. Biologische boeren kunnen die druk verlichten door het materiaal na compostering te gebruiken. Sinds enkele jaren onderzoekt het Louis Bolk Instituut de mogelijkheden. Landbouwkundige, natuurlijke en juridische overwegingen spelen een rol

Unraveling idea development in discourse trajectories

Conference Theme: The Future of LearningShort Paper Session: SP 6.7With the present paper we want to shed light onto an issue that is central within the knowledge building theory but only little studied – the development of ideas in collaborative learning discourse. Starting from the construction of a network of explicit and implicit relations between ideas, we apply a scientometric method to tackle the temporality of collaborative processes based on the structure of successive ideas. The resulting discourse trajectories are shown to give a holistic and also a detailed view on how knowledge advances when their interpretation is combined with a qualitative analysis of the content of the ideas and their relations. The weighted relevance of relations between ideas enables the identification of sub-topics in the discourse, important ideas, and influence or uptake events.postprintThe 10th International Conference of the Learning Sciences (ICLS 2012), Sydney, Australia, 2-6 July 2012. In ICLS 2012 Proceedings, 2012, v. 2, p. 162-16

Burgercooperaties: Speler of speelbal in de nieuwe verhoudingen tussen overheid, markt en samenleving

Burgers hebben in Nederland het afgelopen decennium in allerlei sectoren initiatieven ontwikkeld en coöperaties opgericht om zelf voorzieningen en diensten tot stand te brengen en te beheren. Kennelijk slagen overheid en markt er onvoldoende in om in bepaalde behoeften en daarmee samenhangende waarden van burgers leven te voorzien. Hoewel burgercoöperaties jonge organisaties zijn die zichzelf grotendeels nog moeten bewijzen, zijn de koplopers een bron van inspiratie, innovatie en navolging. Tegelijk kunnen we constateren dat er weinig kennis beschikbaar is over deze nieuwe organisatievorm. Het ontbreekt tot nu toe aan empirische sectorstudies en een systematische vergelijking. Dit themanummer inventariseert en vergelijkt the state of art van burgercoöperaties op het terrein van energie, zorg, breedband en wonen. Hoe effectief en duurzaam zijn burgercoöperaties en hoe verhouden ze zich tot overheden, marktpartijen en maatschappelijke organisaties? De vergelijkende analyse laat zien dat burgercoöperaties moeten leren om te gaan met de spanning tussen het streven naar zelfbeheer en de behoefte tot professionalisering. Ook moeten ze leren samen te werken met andere partijen in hun omgeving. Coöperaties moeten leren het spel mee te spelen zodat zij geen speelbal van andere partijen worden

Organic fertilisers of the MAC trial and their impact on soil quality, environment and climate change.

After 8 years, the MAC field trial in Lelystad, the Netherlands, shows the effects of different fertiliser strategies, ranging from animal manure to plant compost to mineral fertiliser. The impact on yield, soil quality, soil health, environment and climate change is discussed. The trial is unique in monitoring th eeffect of so many types of fertilisers over so many years

Diminished temperature and vegetation seasonality over northern high latitudes

Global temperature is increasing, especially over northern lands (>50° N), owing to positive feedbacks1. As this increase is most pronounced in winter, temperature seasonality (ST)—conventionally defined as the difference between summer and winter temperatures—is diminishing over time2, a phenomenon that is analogous to its equatorward decline at an annual scale. The initiation, termination and performance of vegetation photosynthetic activity are tied to threshold temperatures3. Trends in the timing of these thresholds and cumulative temperatures above them may alter vegetation productivity, or modify vegetation seasonality (SV), over time. The relationship between ST and SV is critically examined here with newly improved ground and satellite data sets. The observed diminishment of ST and SV is equivalent to 4° and 7° (5° and 6°) latitudinal shift equatorward during the past 30 years in the Arctic (boreal) region. Analysis of simulations from 17 state-of-the-art climate models4 indicates an additional STdiminishment equivalent to a 20° equatorward shift could occur this century. How SV will change in response to such large projected ST declines and the impact this will have on ecosystem services5 are not well understood. Hence the need for continued monitoring6 of northern lands as their seasonal temperature profiles evolve to resemble thosefurther south.Lopullinen vertaisarvioitu käsikirjoitu

Analyse der Tätigkeiten kardiovaskulärer Gewebebanken in Deutschland in den Jahren 2007 bis 2010

__Background:__ Especially in complicated aortic valve endocarditis, infections of the aorta by mycotic aortic aneurysms and prosthetic infections, or as part of the Ross procedure, the use of allogeneic heart valve transplants remains important. The production of such allografts in Germany is the task of cardiovascular tissue banks (CVTB). __Materials and methods:__ During an analysis of the years 2007-2010, basic data on donor numbers, production, and distribution as well as the technical conditions of not only the four participating CVTB (Bad Oeynhausen, Berlin, Kiel, Munich) but also data from the CVTB Rotterdam as an external reference were recorded. __Results:__ The German CVTB delivered an average of 44 aortic and 95 pulmonary allografts per year to clinical users. By incorporating the annually imported valve allografts, the demand in Germany approximately averages 220 heart valve allografts per year. The heart tissue was harvested from approximately 100 multiorgan donors, 45 cardiovascular deaths, and 80 domino donors annually. __Discussion:__ The participating cardiovascular tissue banks have comparable technical and administrative requirements and are able to produce tissue preparations according to the rules of Good Professional Practice in accordance with § 3 (3) AMWHV to assess their quality, whereby harmonization of microbiological monitoring and antibiotic treatment is still necessary

Microfluidic systems for the analysis of the viscoelastic fluid flow phenomena in porous media

In this study, two microfluidic devices are proposed as simplified 1-D microfluidic analogues of a porous medium. The objectives are twofold: firstly to assess the usefulness of the microchannels to mimic the porous medium in a controlled and simplified manner, and secondly to obtain a better insight about the flow characteristics of viscoelastic fluids flowing through a packed bed. For these purposes, flow visualizations and pressure drop measurements are conducted with Newtonian and viscoelastic fluids. The 1-D microfluidic analogues of porous medium consisted of microchannels with a sequence of contractions/ expansions disposed in symmetric and asymmetric arrangements. The real porous medium is in reality, a complex combination of the two arrangements of particles simulated with the microchannels, which can be considered as limiting ideal configurations. The results show that both configurations are able to mimic well the pressure drop variation with flow rate for Newtonian fluids. However, due to the intrinsic differences in the deformation rate profiles associated with each microgeometry, the symmetric configuration is more suitable for studying the flow of viscoelastic fluids at low De values, while the asymmetric configuration provides better results at high De values. In this way, both microgeometries seem to be complementary and could be interesting tools to obtain a better insight about the flow of viscoelastic fluids through a porous medium. Such model systems could be very interesting to use in polymer-flood processes for enhanced oil recovery, for instance, as a tool for selecting the most suitable viscoelastic fluid to be used in a specific formation. The selection of the fluid properties of a detergent for cleaning oil contaminated soil, sand, and in general, any porous material, is another possible application

The importance of shared environment in infant-father attachment: A behavioral genetic study of the Attachment Q-Sort

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