A Cross Country Comparison of the Development of the Organic Sector in Denmark, Germany, United Kingdom and the Netherlands

The aim of this article is to test the thesis "commitment of retail chains as well as favourable policy conditions are the main drivers of the steady market growth of organic agriculture in Europe." (Yussefi and Willer, 2003). Therefore, the role of government policy and of retail chains in four European countries - Denmark, Germany, the United Kingdom and the Netherlands - are analysed. It seems that the collaboration between government, chain participants and NGOs is of considerable importance, in which active stimulation and the provision of guidance to the channel from the retail chains, in combination with an active and stimulating government policy, can cause an impulse in growth. It should be noted that other factors must also be present in order for market players to convert; likewise, consumer demand should be well developed.Farm Management,

Space-based retrievals of air-sea gas transfer velocities using altimeters: Calibration for dimethyl sulfide

This study is the first to directly correlate gas transfer velocity, measured at sea using the eddy-correlation (EC) technique, and satellite altimeter backscattering. During eight research cruises in different parts of the world, gas transfer velocity of dimethyl sulfide (DMS) was measured. The sample times and locations were compared with overpass times and locations of remote sensing satellites carrying Ku-band altimeters: ERS-1, ERS-2, TOPEX, POSEIDON, GEOSAT Follow-On, JASON-1, JASON-2 and ENVISAT. The result was 179 pairs of gas transfer velocity measurements and backscattering coefficients. An inter-calibration of the different altimeters significantly reduced data scatter. The inter-calibrated data was best fitted to a quadratic relation between the inverse of the backscattering coefficients and the gas transfer velocity measurements. A gas transfer parameterization based on backscattering, corresponding with sea surface roughness, might be expected to perform better than wind speed-based parameterizations. Our results, however, did not show improvement compared to direct correlation of shipboard wind speeds. The relationship of gas transfer velocity to satellite-derived backscatter, or wind speed, is useful to provide retrieval algorithms. Gas transfer velocity (cm/hr), corrected to a Schmidt number of 660, is proportional to wind speed (m/s). The measured gas transfer velocity is controlled by both the individual water-side and air-side gas transfer velocities. We calculated the latter using a numerical scheme, to derive water-side gas transfer velocity. DMS is sufficiently soluble to neglect bubble-mediated gas transfer, thus, the DMS transfer velocities could be applied to estimate water-side gas transfer velocities through the unbroken surface of any other gas Key Points: - Show relations between altimeter data and field values of air-sea gas transfer - DMS gas transfer velocity can be used to estimate direct gas transfer of any gas - Direct gas transfer velocity (for Sc = 660) is roughly double 10 m wind spee

The OceanFlux Greenhouse Gases methodology for deriving a sea surface climatology of CO2 fugacity in support of air–sea gas flux studies

Climatologies, or long-term averages, of essential climate variables are useful for evaluating models and providing a baseline for studying anomalies. The Surface Ocean CO2 Atlas (SOCAT) has made millions of global underway sea surface measurements of CO2 publicly available, all in a uniform format and presented as fugacity, fCO2. As fCO2 is highly sensitive to temperature, the measurements are only valid for the instantaneous sea surface temperature (SST) that is measured concurrently with the in-water CO2 measurement. To create a climatology of fCO2 data suitable for calculating air–sea CO2 fluxes, it is therefore desirable to calculate fCO2 valid for a more consistent and averaged SST. This paper presents the OceanFlux Greenhouse Gases methodology for creating such a climatology. We recomputed SOCAT's fCO2 values for their respective measurement month and year using monthly composite SST data on a 1° × 1° grid from satellite Earth observation and then extrapolated the resulting fCO2 values to reference year 2010. The data were then spatially interpolated onto a 1° × 1° grid of the global oceans to produce 12 monthly fCO2 distributions for 2010, including the prediction errors of fCO2 produced by the spatial interpolation technique. The partial pressure of CO2 (pCO2) is also provided for those who prefer to use pCO2. The CO2 concentration difference between ocean and atmosphere is the thermodynamic driving force of the air–sea CO2 flux, and hence the presented fCO2 distributions can be used in air–sea gas flux calculations together with climatologies of other climate variables

Naar een gereedschapskist voor transitiemonitoring: Een verkenning van de bruikbaarheid van methoden, modellen en concepten uit de strategisch management-, diffusie- en sociale netwerkliteratuur

This report explores the applicability of a number of methods, models, and concepts from the literature on strategic management, diffusion, and social networks with respect to the monitoring of transition processes. First, transition theory is analysed to identify aspects that should be monitored. Subsequently, the possible contribution of the various methods, models, and concepts to monitor these aspects is determined. In dit rapport wordt voor een aantal methoden, modellen en concepten uit de strategisch management-, diffusie- en sociale netwerkliteratuur verkend wat de toepassingsmogelijkheden zijn in het kader van transitiemonitoring. Daartoe wordt eerst uit de transitietheorie afgeleid welke aspecten in kaart moeten worden gebracht. Vervolgens wordt voor de verschillende methoden, modellen en concepten nagegaan aan welke toepassingen een bijdrage kan worden geleverd.Institutional and Behavioral Economics,

On the calculation of air-sea fluxes of CO2 in the presence of temperature and salinity gradients

The presence of vertical temperature and salinity gradients in the upper ocean and the occur- rence of variations in temperature and salinity on time scales from hours to many years complicate the calculation of the flux of carbon dioxide (CO2) across the sea surface. Temperature and salinity affect the interfacial concentration of aqueous CO2 primarily through their effect on solubility with lesser effects related to saturated vapor pressure and the relationship between fugacity and partial pressure. The effects of temperature and salinity profiles in the water column and changes in the aqueous concentration act primarily through the partitioning of the carbonate system. Climatological calculations of flux require atten- tion to variability in the upper ocean and to the limited validity of assuming ‘‘constant chemistry’’ in trans- forming measurements to climatological values. Contrary to some recent analysis, it is shown that the effect on CO2 fluxes of a cool skin on the sea surface is large and ubiquitous. An opposing effect on calculated fluxes is related to the occurrence of warm layers near the surface; this effect can be locally large but will usually coincide with periods of low exchange. A salty skin and salinity anomalies in the upper ocean also affect CO2 flux calculations, though these haline effects are generally weaker than the thermal effects

Groot, groter, ..duurzaamst!? Percepties van burgers ten aanzien van schaalgrootte en schaalvergroting in de agrarische sector

In de belevingswereld van een relatief grote groep burgers is er geen uitgesproken mening met betrekking tot het verschil tussen grote en kleine landbouwbedrijven. Een eventuele concentratie van de Nederlandse land- en tuinbouw is echter niet gewenst. Dat blijkt uit een onderzoek van het LEI naar de percepties van burgers ten aanzien van schaalgrootte in de landbou

Concurrentiekracht biologisch varkensvlees : een internationale vergelijking

Nederland is een sterke speler in de productie van biologisch varkensvlees in Noordwest-Europa. Het niveau van de productiekosten in de biologische varkenshouderij in Duitsland en Denemarken ligt lager dan in Nederland. Denemarken is een geduchte concurrent. Maar door een efficiënte organisatie van de productieketen is Nederland in staat rendabel te concurreren. Afzet naar Duitsland en het VK vergt een specifieke aanpak

Macht en prijsvorming in agrofoodketens

Deze studie onderzoekt de prijstransmissie in de Nederlandse ketens voor rundvlees, kalfsvlees, varkensvlees, pluimveevlees, consumptieaardappelen en patates frites. Er wordt een connectie gemaakt met de empirie en bestaande literatuur over prijstransmissie, marktmacht en mededingingsbeleid. Modelmatig wordt de prijsoverdracht in de diverse ketens vastgestel