5,931 research outputs found
PROJECT: Green Crop Lifting – an Alternative Producing Healthy Seed Potatoes in the System of Organic Farming
The standards of organic farming require the use of organically grown seeds in organic potato farming. Presumably the use of conventionally grown seeds under exceptional circumstances will end in 2003. Only organically grown seeds can be used thereafter. Therefore, it is important to check alternatives for organic potato seed production, which will reduce the cultivation risk, guarantee a high quality of seed potatoes (virus-free and healthy seed), and increase the fraction of marketable potatoes. On 7 farms in Northern Germany (4 sites in the coastal region (Schleswig-Holstein) and 3 sites in the inland region (Lower Saxony)) the green crop lifting (GCL) at two different dates was checked against the traditional process (haulm cutting) and a control plot (natural senescence) with regard to the effect of presprouting in the years 1999 to 2001. The focus of the investigation was the amount of viral load (tested with ELISA) and detection of other diseases (valuation) on / in the harvested potatoes. Yield reduction and tuber damage was recorded. Flying activity of aphids was monitored by yellow water traps.In the coastal region a very low pressure of aphids was observed over the three years. In contrast there was a higher pressure of aphids in the inland region, but only 1999 brought an early and outstanding pressure. In peak times (middle of July 1999) the number of aphids was more than 12 times higher compared to the coastal region. Only in 2000 an early aphid pressure was recorded in the middle of May. If there was a high pressure of aphids the early green crop lifting (in the middle of July) was an effective way reducing the virus diseases.Caused by the early date of GCL the total tuber yield reduction averaged out at 18,8 % over the three years compared to the control. Related to the marketable seed potatoes (28-50 mm) the yield reduction amounted 14.1 % only
Mori-Tanaka models for the thermal conductivity of composites with interfacial resistance and particle size distributions
Low temperature alteration carbonates in the ocean crust and their importance for CO2 uptake and the global Ca cycle
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Against wasted politics: a critique of the circular economy
The discourse of zero-waste and the circular economy has been championed by key players, such as the European Commission, management consultancies, NGOs, academics and multinational companies, in recent years. Given the all too obvious social and environmental crises associated with out-of-bounds growth capitalism, the circular
economy has been one of the main references for rebuilding and reforming a political economy of sustainable growth. In this paper we detect a de-politicizing strategy in this attempt of reform, and, consequently, aim at re-locating a position for the politicization of growth-driven capitalism and the circular economy. We do this by offering a unique
discursive-material theoretical framework, bringing together Marxist and Lacanian psychoanalytic readings. This will allow understanding both the subjective relation with the meaning of waste and the material exchanges that place the subject in the position to
produce and consume waste as a valuable commodity. In our quest to (re-)politicize waste, we offer three practical steps that aim at interrupting the endless repetition of
waste, which include attempts to eradicate it. This argument will be illustrated by making reference to the circular strategies of Apple Inc., the world’s largest and most iconic consumer electronics company
On the 2-categories of weak distributive laws
A weak mixed distributive law (also called weak entwining structure) in a
2-category consists of a monad and a comonad, together with a 2-cell relating
them in a way which generalizes a mixed distributive law due to Beck. We show
that a weak mixed distributive law can be described as a compatible pair of a
monad and a comonad, in 2-categories extending, respectively, the 2-category of
comonads and the 2-category of monads. Based on this observation, we define a
2-category whose 0-cells are weak mixed distributive laws. In a 2-category K
which admits Eilenberg-Moore constructions both for monads and comonads, and in
which idempotent 2-cells split, we construct a fully faithful 2-functor from
this 2-category of weak mixed distributive laws to K^{2 x 2}.Comment: 15 pages LaTeX source, final version to appear in Comm. Algebr
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