Weitere Selektionsuntersuchungen an Schleppnetzsteerten für den Plattfischfang in der Ostsee

The presentation includes investigations and results regarding Baltic flatfish selectivity with different trawl codend constructions. These investigations were carried out 1999/ 2000 on board of FRV “Clupea” and a commercial 17 m cutter. As could be shown, both an enlarged mesh size and another mesh form than rhombic can improve the selectivity of these fish. As flatfish catches with trawls mostly also cover cod, this mixed fishery at the southern Baltic coast should in future be managed by differentiated technical regulations for an improved selectivity. The results, also based on UW observations, current measurements, and wind tunnel tests with models, demonstrate some possible technical solutions

A neutral hydrogen survey of the Hydra 1 cluster

We are undertaking a project to image the entire volume of the Hydra 1 cluster of galaxies in neutral hydrogen using the VLA. This involves making a series of pointings spaced 30 min. (the half power beam width) apart, each observed at three velocity settings in order to span the whole velocity range of the cluster. The purpose of this survey is to determine the true distribution, both in space and velocity, of gas-rich systems and hence, to deduce what effects a dense environment may have on the evolution of these systems. Most surveys of clusters to date have been performed on optically selected samples. However, optically selected samples may provide misleading views of the distribution of gas-rich systems, since many low surface brightness galaxies have an abundance of neutral gas (Bothun et al. 1987, Giovanelli & Haynes 1989). The Hydra project is providing the first unbiased view of the HI distribution in a cluster of galaxies. Our 5 sigma sensitivity is 4.1 x 10(exp 7) solar M/beam, (assuming H(sub 0) = 75 km s(exp -1) Mpc(exp -1)) and our velocity resolution is 42 km s(exp -1). We have a spatial resolution of 45 sec., which means that only the largest galaxies are spatially resolved enough to determine HI disk size. Our coverage is about 50 percent of the central region plus eight other fields centered on bright spirals within about 2 deg. of the center

The Organic Market in Switzerland and the EU - Overview and market access information for producers and international trading companies

The organic market is highly diverse. Production standards and certification and trade rules place considerable demands upon market participants. At the same time, this market holds out excellent opportunities for creative and circumspect producers, processors and traders. To operate successfully in organic import and export business alike, it is crucial to have accurate information on the potential of the specific organic market and on the conditions governing market access. The attractively designed handbook offers the very latest market information for producers an international trading companies, organized both by product group an by country on 80 pages. This second edition is updated in all chapters and has in addition three new markets: Austria, Italy and Sweden. In addition, the handbook provides an easily accessible overview of the - in some instances - quite complicates - import requirements applicable in Switzerland and the EU. In a further 50-page appendix, the handbook contains an extensive collection of addresses (trading companies, authorities, certification bodies, organizations etc.) and Internet Websites. The second edition of this handbook has been produced in English

Selektionsuntersuchungen an Schleppnetzsteerten für den Plattfischfang in der Ostsee

The intensified trawl fishery for flounder and otherflatfishes along the German Baltic coast during summer months resulted in the problem of increased undersized bycatches and their discarding. Thereforeselectivity trials with a standard codend, a codend withenlarged meshes and a so-called multipanel codendwith partly transverse netting were investigated. Results show that improvements in selectivity are possible, and tests including UW-TV observations shouldbe continued

A discrete evolutionary genetic model for the emergence of metabolic resistance

Metabolic resistance refers to the biochemical processes within the plant that degrade herbicides to less toxic compounds, resulting in a shift of the dose-response curve. A multi allelic fitness model is used to simulate the emergence of metabolic resistance. A diploid population with a single resistance locus is considered with K number of alleles. The joint evolutionary dynamics model as described by HUILLET and MARTINEZ (2011) is applied to the dynamics of metabolic resistance. This is achieved by relating the fitness parameters to the form of the dose response curve which is characterized by a steepness and a threshold parameter (ED50 value). It is assumed that the threshold parameter of individuals in a population is log-normally distributed as the result of normal genetic variation. This means that there are only very few individuals with a high degree of metabolic resistance (high threshold parameter) in a weed population if no herbicides are applied. Under the long term application of only herbicide with one mode of action, the model produces the gradual shift of the mean dose response curve of the model weed population as frequently observed in the field. The model is used to understand the dynamics of the development of metabolic resistance under field conditions.Keywords: Evolution, genetic model, metabolic resistance, multi-allelic fitness modelEin zeitdiskretes genetisches Modell für die Entwicklung metabolischer ResistenzMetabolische Resistenz ist die Fähigkeit eines Organismus, toxische Substanzen abzubauen, was zu einer Verschiebung von Dosis-Wirkungskurven (ED50-Werte) führt. Ein generelles genetisches Modell (HUILLET und MARTINEZ, 2011) für eine diploide Population mit einem einzelnen Resistsnz-Lokus und K Allelen wurde auf das Auftreten von metabolischer Resistenz angewendet. Dazu wurden die Fitnesskoeffizienten mit einer Dosiswirkungskurve verknüpft. Die Form der Kurve ist durch einen Schwellenwert (ED50-Wert) und einen Formparameter für die Steigung bestimmt. Jedes Allel Ai trägt zur Expression von einem bestimmen Schwellenwert innerhalb des Individuums bei. Es wird angenommen, dass der Schwellenwert in einer unbehandelten Population logarithmisch normalverteilt ist, d.h. die Frequenz von Individuen mit hohen ED50-Werten ist äußerst gering. Das Modell liefert die Verschiebung der Dosiswirkungskurve einer Population unter der kontinuierlichen Anwendung von Herbiziden mit dem gleichen Wirkungsmechanismus und wird dazu verwendet, Managementverfahren zur Verzögerung des Auftretens der metabolischen Resistenz zu bewerten.Stichwörter: Evolution, genetisches Modell, metabolische Resistenz, Resistenzmanagemen

Model for metabolic resistance against ALS inhibitors

Due to herbicide selection pressure metabolic resistance has evolved in many weed species. In this paper we analyse the interaction between the branched chain amino acid (BBC) pathway and detoxifying pathways for herbicide breakdown. The four phase detoxification pathway of herbicides comprising the action of P450, GST, glycosyltransferase and ABC transporter is modelled by a system of coupled enzyme kinetic reactions represented by nonlinear differential equations. The herbicide under consideration inhibits the enzyme ALS, which is the key enzyme for the biosynthesis of branched amino acids. For the kinetics of ALS a Monod approach is employed with a binding site for the inhibitor. Synthetic and detoxification pathways are coupled. The model is used to study the production of branched amino acids under the action of ALS inhibitors for different structures and modes of action of the detoxification pathway. The model is capable of generating typical dose response curves and their shift in dependence of the activity pattern of the enzymes of the detoxification pathway of the inhibitor.Keywords: ALS inhibitor, branched chain amino acid biosynthesis, enzyme kinetics, metabolic resistance, metabolic networkEin Modell für die metabolische Resistenz gegen ALS InhibitorenZusammenfassung Metabolische Resistenz beinhaltet die Fähigkeit eines Organismus, toxische Substanzen abzubauen, was zu einer Verschiebung von Dosis-Wirkungskurven führt. In diesem Beitrag wird die Dynamik des Zusammenspiels der Biosynthese der verzweigtkettigen Aminosäuren mit dem Abbauweg für einen ALS Inhibitor anhand eines mathematischen Modelles untersucht. Dieses besteht aus einem System von gekoppelten enzymatischen Reaktionen, dargestellt durch nichtlineare Differentialgleichungen. Die ALS Kinetik wird durch einen Monod Ansatz beschrieben mit Pyruvat als Substrat und einer Bindungsstelle für einen nichtkompetitiven Inhibitor. Das Modell liefert typische Dosis Wirkungskurven und die Verschiebung des ED50-Wertes zu höheren Dosen in Abhängigkeit vom Aktivitätsmuster des Abbauweges für den Inhibitor. Stichwörter: ALS Inhibitor, Biosynthese von Aminosäuren, Enzymkinetik, metabolische Netzwerke, metabolische Resisten