Suchergebnisse

Community Organizing (CO) hat sich als Ansatz demokratischen Handelns in den 1930er Jahren in den USA entwickelt und seit den 1990er Jahren auch in Deutschland etabliert. Vor dem Hintergrund einer starken Politikverdrossenheit sowie von Spaltungstendenzen innerhalb der Gesellschaft lohnt es sich, diese demokratische Tradition neu kennenzulernen und auf ihre gegenwärtigen Potenziale hin zu reflektieren. In der Publikation werden für diesen Zweck Grundlagentexte, Fachartikel sowie Erfahrungsberichte des Broad-Based Community Organizing zusammengeführt und in einen aktuellen Gesamtzusammenhang gesetzt.

Drought stress affects yield formation and quality of sugar beet. The aim of this study was to identify the growing period, in which drought stress has the greatest impact on growth, and furthermore, to analyze the response of different sugar beet genotypes. Causes for a different response should be identified. In pot experiments in the greenhouse, drought stress was simulated by reducing irrigation to 60% of the water holding capacity (WHC) for four weeks at various growth stages followed by re-watering. Growth reduction was greatest when drought stress occurred early in the season: the content of the quality-determining non-sugars was highest, sugar yield and beet diameter were lowest. Responses of the genotypes in sugar yield, but primarily in the accumulation of osmotically active substances differed. Despite re-watering after drought stress the restrictions could not be compensated during growth. The transpiration coefficient of the drought-stressed treatments was only slightly different to the control, because water consumption in the control did not either increase at average air temperatures beyond 23 °C. The strong effect of early drought stress could be attributed to the high growth rates, so that a limited water supply affected yield formation more than at later growth stages. The storage losses of sugar beet genotypes are closely related to damage during harvest and subsequent infestation with mould and rots. Genetic variation for storability seems to be primarily linked to textural properties of the roots such as the resistance against mechanical damage. However, no information is available about the tissue strength, tissue composition and structural organization leading to an enhanced resistance against damage and pathogen attack. Therefore, the aims of the study were the identification of genotypic differences concerning tissue strength of the beet, the relation to damage and pathogen infestation and the underlying physiological basis of tissue strength. Field trials were carried out with 6 genotypes at 2 locations in 2018. The roots were harvested in August and November. After harvest in November, a storage trial was carried out. The root strength increased from August to November. Beets with a high puncture resistance of the periderm also had a firm inner tissue. Genotypic differences in puncture resistance were not affected by the harvest time, indicating that this trait is stable throughout the growing period. A higher puncture resistance of the beet was related to a lower mould growth during storage. Genotypes with varying tissue strength also differed in fiber content (AIR), but the composition of AIR was stable over genotypes. The number of cambium rings seems not to essentially influence the tissue strength of the beet. In the further course of the project, microscopic analyzes will clarify, whether genotypic differences in tissue strength can be attributed to cell size or cell wall thickness.

Quantum dots are known to confine electrons within their structure. Whenever they periodically aggregate into arrays and cooperative interactions arise, novel quantum properties suitable for technological applications show up. Control over the potential barriers existing between neighboring quantum dots is therefore essential to alter their mutual crosstalk. Here we show that precise engineering of the barrier width can be experimentally achieved on surfaces by a single atom substitution in a haloaromatic compound, which in turn tunes the confinement properties through the degree of quantum dot intercoupling. We achieved this by generating self-assembled molecular nanoporous networks that confine the two-dimensional electron gas present at the surface. Indeed, these extended arrays form up on bulk surface and thin silver films alike, maintaining their overall interdot coupling. These findings pave the way to reach full control over two-dimensional electron gases by means of self-assembled molecular networks. ; This work was supported in part by the Spanish Ministry of Economy (grants MAT2013-46593-C6-4-P, MAT2016-78293-C6-6-R and FIS2013-48286-C2-1-P), by the Spanish Research Council (CSIC- 201560I022), by the Basque Government (grants IT621-13 and IT-756-13), by the Japan Science and Technology Agency (JST), 'Precursory Research for Embryonic Science and Technology' (PRESTO) for a project of 'Molecular technology and creation of new function', by JSPS KAKENHI Grant Number 15K21765, by the Swiss National Science Foundation, by the Swiss Nanoscience Institute, and by COST Action (European Cooperation in Science and Technology) MP1303. Swiss National Supercomputing Center in Lugano (Project s499 and s621) is acknowledged. ; Peer Reviewed