762 research outputs found

    Themenplattformen zur Förderung der innovativen regionalen Entwicklung im ökologischen Landbau

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    Ausgangslage Sowohl das Bundesprogramm Ökologischer Landbau als auch das Bundesprogramm „Regionen aktiv – Land gestaltet Zukunft“ streben eine Steigerung der Nachfrage nach regionalen QualitĂ€tsprodukten (inkl. Öko-Produkten), Dienstleistungen und vor allem nach einer Kombination beider an. Auch das LEADER+-Programm fördert diese AnsĂ€tze. Ein systematischer inhaltlicher Austausch ĂŒber Ergebnisse der AktivitĂ€ten in den Regionen und die Wirksamkeit der verschiedenen Maßnahmen sowie eine Anleitung bzw. Hilfestellung zur Umsetzung der Ergebnisse finden nicht statt. Ziel des Projekts war es Konzepte fĂŒr eine Etablierung geeigneter ĂŒberregionaler Strukturen zu entwickeln, um interregionale Kommunikations- und Qualifizierungsprozesse zu unterstĂŒtzen. Methodik Die vorliegende Untersuchung verfolgte einen induktiven Forschungsansatz. Auf der Basis vorhandener Erfahrungen in verschiedenen Regionen wurden mit Vertretern aus den Regionen drei „Themenplattformen“ konzipiert mit dem Ziel, Empfehlungen fĂŒr die Förderung interregionaler Vernetzungs- und Lernprozesse abzuleiten: 1. Themenplattform Erlebnisort Bauernhof: Dr. Christian Ganzert 2. Themenplattform Pferd: Dr. Gerlind Brinkmann 3. Themenplattform Milchvermarktung: Beate Huber Ergebnisse - Der Austausch regionaler Initiativen muss als Weiterbildungs- und QualitĂ€tsentwicklungsmaßnahme verstĂ€rkt durch die öffentliche Hand unterstĂŒtzt werden. - Motor fĂŒr den Informationsaustausch kann eine zentrale Stelle sein, z. B. eine professionelle Koordinationsstelle. Vorteilhaft wĂ€re die Ankopplung der zentralen Stelle an bestehende Strukturen, um evtl. auf bestehende KapazitĂ€ten zurĂŒckgreifen zu können. Ein Ansatz wĂ€re, den Gedanken der LEADER+-Vernetzungsstelle auszubauen. - In der Regel ist insbesondere zur Initiierung einer Themenplattform ein Impuls durch einen externen Koordinator erforderlich. - VerbĂ€nde eignen sich als Initiatoren bzw. können den institutionellen Rahmen fĂŒr Themenplattformen bieten, wenn sie nicht Partikularinteressen vertreten. - Eine Finanzierung sollte nicht nur fĂŒr kompetente Koordination, Moderation und Konfliktmanagement, sondern auch fĂŒr die Einbindung externer Experten sowie externer Netzwerke genutzt werden. - Neue Projekte und Initiativen melden oft einen kurzfristigen spontanen Bedarf fĂŒr einen Informationsaustausch mit Ă€hnlichen Projekten/Initiativen an. Initiativen, die schon lĂ€nger ein spezifisches Thema verfolgen, haben eher ein Interesse an strategischen Fragestellungen. Beide Typen bringen unterschiedliche Anforderungen an die Koordination mit sich. - Die Projekte/Initiativen sollten ihre Beteiligung als Eigenleistung einbringen. Ist eine Honorierung „unterschwellig“, steht der eigene Nutzen des Austausches an erster Stelle. Dies zwingt die Koordination dazu, das Austauschangebot am Bedarf zu orientieren

    Automated Monitoring of the Establishment of the Adsorption Equilibrium: Adsorption of Polyethylene from 1,2,4-Trichlorobenzene onto a Zeolite at Temperature 140°C

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    The automated procedure for the monitoring of the adsorption process in the solute-sorbent-solvent system has been elaborated. It uses commercially available instrument CRYSTAF model 200. The application of CRYSTAF enabled monitoring of adsorption of linear polyethylene with weight average molar masses of 2, 14, and 53 kg/mol from 1,2,4-trichlorobenzene onto zeolite SH-300 at temperature as high as 140°C. It is the authors' understanding that this is the first demonstration of an adsorption isotherms for polyethylene. The measurement with the CRYSTAF instrument reduces manual manipulations with dangerous solvents at high temperature and enables automated long-time monitoring of the concentration of the solute in an adsorption system

    Estimating Bat and Bird Mortality Occurring at Wind Energy Turbines from Covariates and Carcass Searches Using Mixture Models

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    Environmental impacts of wind energy facilities increasingly cause concern, a central issue being bats and birds killed by rotor blades. Two approaches have been employed to assess collision rates: carcass searches and surveys of animals prone to collisions. Carcass searches can provide an estimate for the actual number of animals being killed but they offer little information on the relation between collision rates and, for example, weather parameters due to the time of death not being precisely known. In contrast, a density index of animals exposed to collision is sufficient to analyse the parameters influencing the collision rate. However, quantification of the collision rate from animal density indices (e.g. acoustic bat activity or bird migration traffic rates) remains difficult. We combine carcass search data with animal density indices in a mixture model to investigate collision rates. In a simulation study we show that the collision rates estimated by our model were at least as precise as conventional estimates based solely on carcass search data. Furthermore, if certain conditions are met, the model can be used to predict the collision rate from density indices alone, without data from carcass searches. This can reduce the time and effort required to estimate collision rates. We applied the model to bat carcass search data obtained at 30 wind turbines in 15 wind facilities in Germany. We used acoustic bat activity and wind speed as predictors for the collision rate. The model estimates correlated well with conventional estimators. Our model can be used to predict the average collision rate. It enables an analysis of the effect of parameters such as rotor diameter or turbine type on the collision rate. The model can also be used in turbine-specific curtailment algorithms that predict the collision rate and reduce this rate with a minimal loss of energy production.German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety/FKZ 0327638 A,

    Resistance to host antimicrobial peptides mediates resilience of gut commensals during infection and aging in Drosophila

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    Resilience to short-term perturbations, like inflammation, is a fundamental feature of microbiota, yet the underlying mechanisms of microbiota resilience are incompletely understood. Here, we show that Lactiplantibacillus plantarum, a major Drosophila commensal, stably colonizes the fruit fly gut during infection and is resistant to Drosophila antimicrobial peptides (AMPs). By transposon screening, we identified L. plantarum mutants sensitive to AMPs. These mutants were impaired in peptidoglycan O-acetylation or teichoic acid D-alanylation, resulting in increased negative cell surface charge and higher affinity to cationic AMPs. AMP-sensitive mutants were cleared from the gut after infection and aging-induced gut inflammation in wild-type, but not in AMP-deficient flies, suggesting that resistance to host AMPs is essential for commensal resilience in an inflamed gut environment. Thus, our work reveals that in addition to the host immune tolerance to the microbiota, commensal-encoded resilience mechanisms are necessary to maintain the stable association between host and microbiota during inflammation

    Spectral Variability of Quasars in the Sloan Digital Sky Survey. II: The C IV Line

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    We examine the variability of the high-ionizaton C IV line in a sample of 105 quasars observed at multiple epochs by the Sloan Digital Sky Survey. We find a strong correlation between the change in the C IV line flux and the change in the line width, but no correlations between the change in flux and changes in line center and skewness. The relation between line flux change and line width change is consistent with a model in which a broad line base varies with greater amplitude than the line core. The objects studied here are more luminous and at higher redshift than those normally studied for variability, ranging in redshift from 1.65 to 4.00 and in absolute r-band magnitude from roughly -24 to -28. Using moment analysis line-fitting techniques, we measure line fluxes, centers, widths and skewnesses for the C IV line at two epochs for each object. The well-known Baldwin Effect is seen for these objects, with a slope beta = -0.22. The sample has a median intrinsic Baldwin Effect slope of beta = -0.85; the C IV lines in these high-luminosity quasars appear to be less responsive to continuum variations than those in lower luminosity AGN. Additionally, we find no evidence for variability of the well known blueshift of the C IV line with respect to the low-ionization Mg II line in the highest flux objects, indicating that this blueshift might be useful as a measure of orientation.Comment: 52 pages, 14 figures, accepted for publication in Ap

    Colors, magnitudes and velocity dispersions in early-type galaxies: Implications for galaxy ages and metallicities

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    We present an analysis of the color-magnitude-velocity dispersion relation for a sample of 39320 early-type galaxies within the Sloan Digital Sky Survey. We demonstrate that the color-magnitude relation is entirely a consequence of the fact that both the luminosities and colors of these galaxies are correlated with stellar velocity dispersions. Previous studies of the color-magnitude relation over a range of redshifts suggest that the luminosity of an early-type galaxy is an indicator of its metallicity, whereas residuals in color from the relation are indicators of the luminosity-weighted age of its stars. We show that this, when combined with our finding that velocity dispersion plays a crucial role, has a number of interesting implications. First, galaxies with large velocity dispersions tend to be older (i.e., they scatter redward of the color-magnitude relation). Similarly, galaxies with large dynamical mass estimates also tend to be older. In addition, at fixed luminosity, galaxies which are smaller, or have larger velocity dispersions, or are more massive, tend to be older. Second, models in which galaxies with the largest velocity dispersions are also the most metal poor are difficult to reconcile with our data. However, at fixed velocity dispersion, galaxies have a range of ages and metallicities: the older galaxies have smaller metallicities, and vice-versa. Finally, a plot of velocity dispersion versus luminosity can be used as an age indicator: lines of constant age run parallel to the correlation between velocity dispersion and luminosity.Comment: 12 pages, 9 figures. Accepted by A

    Discovery of circularly polarised radio emission from SS 433

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    We report the discovery of circularly polarised radio emission from the radio-jet X-ray binary SS 433 with the Australia Telescope Compact Array. The flux density spectrum of the circular polarization, clearly detected at four frequencies between 1 - 9 GHz, has a spectral index of (-0.9 +/- 0.1). Multiple components in the source and a lack of very high spatial resolution do not allow a unique determination of the origin of the circular polarization, nor of the spectrum of fractional polarization. However, we argue that the emission is likely to arise in the inner regions of the binary, possibly via propagation-induced conversion of linear to circular polarization, and the fractional circular polarization of these regions may be as high as 10%. Observations such as these have the potential to investigate the composition, whether pairs or baryonic, of the ejecta from X-ray binaries.Comment: Accepted for publication in ApJ Letter

    An Empirical Calibration of the Completeness of the SDSS Quasar Survey

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    Spectra of nearly 20000 point-like objects to a Galactic reddening corrected magnitude of i=19.1 have been obtained to test the completeness of the SDSS quasar survey. The spatially-unresolved objects were selected from all regions of color space, sparsely sampled from within a 278 sq. deg. area of sky covered by this study. Only ten quasars were identified that were not targeted as candidates by the SDSS quasar survey (including both color and radio source selection). The inferred density of unresolved quasars on the sky that are missed by the SDSS algorithm is 0.44 per sq. deg, compared to 8.28 per sq. deg. for the selected quasar density, giving a completeness of 94.9(+2.6,-3.8) to the limiting magnitude. Omitting radio selection reduces the color-only selection completeness by about 1%. Of the ten newly identified quasars, three have detected broad absorption line systems, six are significantly redder than other quasars at the same redshift, and four have redshifts between 2.7 and 3.0 (the redshift range where the SDSS colors of quasars intersect the stellar locus). The fraction of quasars missed due to image defects and blends is approximately 4%, but this number varies by a few percent with magnitude. Quasars with extended images comprise about 6% of the SDSS sample, and the completeness of the selection algorithm for extended quasars is approximately 81%, based on the SDSS galaxy survey. The combined end-to-end completeness for the SDSS quasar survey is approximately 89%. The total corrected density of quasars on the sky to i=19.1 is estimated to be 10.2 per sq. deg.Comment: 37 pages, 10 figures, accepted for publication in A

    The Cut & Enhance method : selecting clusters of galaxies from the SDSS commissioning data

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    We describe an automated method, the Cut & Enhance method (CE) for detecting clusters of galaxies in multi-color optical imaging surveys. This method uses simple color cuts, combined with a density enhancement algorithm, to up-weight pairs of galaxies that are close in both angular separation and color. The method is semi-parametric since it uses minimal assumptions about cluster properties in order to minimize possible biases. No assumptions are made about the shape of clusters, their radial profile or their luminosity function. The method is successful in finding systems ranging from poor to rich clusters of galaxies, of both regular and irregular shape. We determine the selection function of the CE method via extensive Monte Carlo simulations which use both the real, observed background of galaxies and a randomized background of galaxies. We use position shuffled and color shuffled data to perform the false positive test. We have also visually checked all the clusters detected by the CE method. We apply the CE method to the 350 deg^2 of the SDSS (Sloan Digital Sky Survey) commissioning data and construct a SDSS CE galaxy cluster catalog with an estimated redshift and richness for each cluster. The CE method is compared with other cluster selection methods used on SDSS data such as the Matched Filter (Postman et al. 1996, Kim et al. 2001), maxBCG technique (Annis et al. 2001) and Voronoi Tessellation (Kim et al. 2001). The CE method can be adopted for cluster selection in any multi-color imaging surveys.Comment: 62 pages, 32 figures, Accepted for publication in the Astronomical Journal, "the CE galaxy cluster catalog can be downloaded from, http://astrophysics.phys.cmu.edu/~tomo/ce/
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