2,011 research outputs found

    Economic Impact of the Mid-Term Review on Agricultural Production, Farm Income and Farm Survival: A Quantitative Analysis for Local Sub-Regions of Schleswig-Holstein in Germany

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    This study analyzes the impact of the Mid-Term Review (MTR) on the agricultural sector in Schleswig-Holstein, a federal state in Germany. First, a very detailed farm group linear programming model is built to quantify the effects on agricultural production and farm incomes. The production adjustment to the MTR and its impact on farm profit vary significantly between individual farms. These results depend mainly on the farm type and the resource endowments of the farms. Second, the impact on structural change is examined with a farm survival model. Although the MTR clearly reduces the incomes of several farm types, it accelerates the structural change only gradually.policy reform, modeling production adjustment, farm income, structural change, Community/Rural/Urban Development, Q12, Q18,

    Local readout enhancement for detuned signal-recycling interferometers

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    Motivated by the optical-bar scheme of Braginsky, Gorodetsky and Khalili, we propose to add to a high power detuned signal-recycling interferometer a local readout scheme which measures the motion of the arm-cavity front mirror. At low frequencies this mirror moves together with the arm-cavity end mirror, under the influence of gravitational waves. This scheme improves the low-frequency quantum-noise-limited sensitivity of optical-spring interferometers significantly and can be considered as a incorporation of the optical-bar scheme into currently planned second-generation interferometers. On the other hand it can be regarded as an extension of the optical bar scheme. Taking compact-binary inspiral signals as an example, we illustrate how this scheme can be used to improve the sensitivity of the planned Advanced LIGO interferometer, in various scenarios, using a realistic classical-noise budget. We also discuss how this scheme can be implemented in Advanced LIGO with relative ease

    Das Gründungsgeschehen in Dresden, Rostock und Karlsruhe: eine Betrachtung des regionalen Gründungspotenzials

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    This paper compares the structure and the development of new firm formation activity in three German regions. The two East German regions, Dresden and Rostock, show significantly higher start-up rates than the West German region Karlsruhe. The analysis of entry cohorts reveals that not only the direct employment effects are more pronounced in Karlsruhe but also the probability of failure is significantly lower in Karlsruhe compared to the two East German regions. The regional potential for innovative new firms is measured by the number of natural scientists and engineers in high-tech industries and public science organizations. This potential is underdeveloped in Rostock while Dresden almost caught up with Karlsruhe. Policy-sponsored networks aiming to increase the number of innovative start-ups exist in all three regions. Dresden and Karlsruhe have successfully launched a considerable number of university start-ups. --Entrepreneurship,new firm formation,entry cohorts,East Germany,research and development,innovation,high-tech industries,start-up promotion,EXIST

    The Impact of Noise and Mismatch on SAR ADCs and a Calibratable Capacitance Array Based Approach for High Resolutions

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    This paper describes widely used capacitor structures for charge-redistribution (CR) successive approximation register (SAR) based analog-to-digital converters (ADCs) and analyzes their linearity limitations due to kT/C noise, mismatch and parasitics. Results of mathematical considerations and statistical simulations are presented which show that most widespread dimensioning rules are overcritical. For high-resolution CR SAR ADCs in current CMOS technologies, matching of the capacitors, influenced by local mismatch and parasitics, is a limiting factor. For high-resolution medium-speed CR SAR ADCs, a novel capacitance array based approach using in-field calibration is proposed. This architecture promises a high resolution with small unit capacitances and without expensive factory calibration as laser trimming

    The VLTI/MIDI survey of massive young stellar objects - Sounding the inner regions around intermediate- and high-mass young stars using mid-infrared interferometry

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    We aim to characterize the distribution and composition of circumstellar material around young massive stars, and to investigate exactly which physical structures in these objects are probed by long-baseline mid-infrared interferometric observations. We used the two-telescope interferometric instrument MIDI of the Very Large Telescope Interferometer of the European Southern Observatory to observe a sample of 24 intermediate- and high-mass young stellar objects in the N band (8-13 micron). We had successful fringe detections for 20 objects, and present spectrally-resolved correlated fluxes and visibility levels for projected baselines of up to 128 m. We fit the visibilities with geometric models to derive the sizes of the emitting regions, as well as the orientation and elongation of the circumstellar material. Fourteen objects in the sample show the 10 micron silicate feature in absorption in the total and correlated flux spectra. For 13 of these objects, we were able to fit the correlated flux spectra with a simple absorption model, allowing us to constrain the composition and absorptive properties of the circumstellar material. Nearly all of the massive young stellar objects observed show significant deviations from spherical symmetry at mid-infrared wavelengths. In general, the mid-infrared emission can trace both disks and outflows, and in many cases it may be difficult to disentangle these components on the basis of interferometric data alone, because of the sparse spatial frequency coverage normally provided by current long-baseline interferometers. For the majority of the objects in this sample, the absorption occurs on spatial scales larger than those probed by MIDI. Finally, the physical extent of the mid-infrared emission around these sources is correlated with the total luminosity, albeit with significant scatter.Comment: 36 pages, 22 figures. Accepted to Astronomy and Astrophysic

    A modular interface of IL-4 allows for scalable affinity without affecting specificity for the IL-4 receptor

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    BACKGROUND: Interleukin 4 (IL-4) is a key regulator of the immune system and an important factor in the development of allergic hypersensitivity. Together with interleukin 13 (IL-13), IL-4 plays an important role in exacerbating allergic and asthmatic symptoms. For signal transduction, both cytokines can utilise the same receptor, consisting of the IL-4Rα and the IL-13Rα1 chain, offering an explanation for their overlapping biological functions. Since both cytokine ligands share only moderate similarity on the amino acid sequence level, molecular recognition of the ligands by both receptor subunits is of great interest. IL-4 and IL-13 are interesting targets for allergy and asthma therapies. Knowledge of the binding mechanism will be important for the generation of either IL-4 or IL-13 specific drugs. RESULTS: We present a structure/function analysis of the IL-4 ligand-receptor interaction. Structural determination of a number of IL-4 variants together with in vitro binding studies show that IL-4 and its high-affinity receptor subunit IL-4Rα interact via a modular protein-protein interface consisting of three independently-acting interaction clusters. For high-affinity binding of wild-type IL-4 to its receptor IL-4Rα, only two of these clusters (i.e. cluster 1 centered around Glu9 and cluster 2 around Arg88) contribute significantly to the free binding energy. Mutating residues Thr13 or Phe82 located in cluster 3 to aspartate results in super-agonistic IL-4 variants. All three clusters are fully engaged in these variants, generating a three-fold higher binding affinity for IL-4Rα. Mutagenesis studies reveal that IL-13 utilizes the same main binding determinants, i.e. Glu11 (cluster 1) and Arg64 (cluster 2), suggesting that IL-13 also uses this modular protein interface architecture. CONCLUSION: The modular architecture of the IL-4-IL-4Rα interface suggests a possible mechanism by which proteins might be able to generate binding affinity and specificity independently. So far, affinity and specificity are often considered to co-vary, i.e. high specificity requires high affinity and vice versa. Although the binding affinities of IL-4 and IL-13 to IL-4Rα differ by a factor of more than 1000, the specificity remains high because the receptor subunit IL-4Rα binds exclusively to IL-4 and IL-13. An interface formed by several interaction clusters/binding hot-spots allows for a broad range of affinities by selecting how many of these interaction clusters will contribute to the overall binding free energy. Understanding how proteins generate affinity and specificity is essential as more and more growth factor receptor families show promiscuous binding to their respective ligands. This limited specificity is, however, not accompanied by low binding affinities

    Khresmoi professional: multilingual, multimodal professional medical search

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    In this demonstration we present the Khresmoi medical search and access system. The system uses a component based architecture housed in the cloud to support target users medical information needs. This includes web systems, computer applications and mobile applications to support the multilingual and multimodal information needs of three test target groups: the general public, general practitioners (GPs) and radiologists. This demonstration presents the systems for GPs and radiologists providing multilingual text and image based (including 2D and 3D radiology images) search functionality

    A Survey for Massive Giant Planets in Debris Disks with Evacuated Inner Cavities

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    The commonality of collisionally replenished debris around main sequence stars suggests that minor bodies are frequent around Sun-like stars. Whether or not debris disks in general are accompanied by planets is yet unknown, but debris disks with large inner cavities - perhaps dynamically cleared - are considered to be prime candidates for hosting large-separation massive giant planets. We present here a high-contrast VLT/NACO angular differential imaging survey for eight such cold debris disks. We investigated the presence of massive giant planets in the range of orbital radii where the inner edge of the dust debris is expected. Our observations are sensitive to planets and brown dwarfs with masses >3 to 7 Jupiter mass, depending on the age and distance of the target star. Our observations did not identify any planet candidates. We compare the derived planet mass upper limits to the minimum planet mass required to dynamically clear the inner disks. While we cannot exclude that single giant planets are responsible for clearing out the inner debris disks, our observations constrain the parameter space available for such planets. The non-detection of massive planets in these evacuated debris disks further reinforces the notion that the giant planet population is confined to the inner disk (<15 AU).Comment: Accepted for publication in Ap

    Mid-infrared interferometry of massive young stellar objects

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    The very inner structure of massive young stellar objects (YSOs) is difficult to trace. With conventional observational methods we identify structures still several hundreds of AU in size. However, the (proto-)stellar growth takes place at the innermost regions (<100 AU) where the actual mass transfer onto the forming high-mass star occurs. We present results from our programme toward massive YSOs at the VLTI, utilising the two-element interferometer MIDI. To date, we observed 10 well-known massive YSOs down to scales of 20 mas (typically corresponding to 20 - 40 AU for our targets) in the 8-13 micron region. We clearly resolve these objects which results in low visibilities and sizes in the order of 30-50 mas. For two objects, we show results of our modelling. We demonstrate that the MIDI data can reveal decisive structure information for massive YSOs. They are often pivotal in order to resolve ambiguities still immanent in model parameters derived from sole SED fitting.Comment: 6 pages, 5 figures, necessary style files iopams.sty, jpconf11.clo, and jpconf.cls included; contribution for the conference "The Universe under the Microscope" (AHAR 2008), held in Bad Honnef (Germany) in April 2008, to be published in Journal of Physics: Conference Series by Institute of Physics Publishing, R. Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.
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