127 research outputs found

    Charakterisierung und Bedeutung außerlandwirtschaftlicher Investoren: Empirische Ergebnisse aus Sicht des landwirtschaftlichen Berufsstandes

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    In den vergangenen Jahren sind die Kauf- und Pachtpreise für landwirtschaftliche Nutzfläche deutschlandweit mit wenigen Ausnahmen deutlich gestiegen. Für den Anstieg werden von vielen Marktexperten zunehmend die Aktivitäten sogenannter nicht- oder außerlandwirtschaftlicher Investoren verantwortlich gemacht, wobei diese Käufergruppe weder homogen noch ohne Weiteres klar abgrenzbar ist. Vor diesem Hintergrund ist im Sommer 2014 eine empirische Erhebung unter Landwirten im gesamten Bundegebiet durchgeführt worden, um in einem ersten Schritt zu klären, anhand welcher Kriterien sich diese außerlandwirtschaftlichen Investoren aus Sicht des Berufsstandes angemessen charakterisieren lassen. Darüber hinaus ist analysiert worden, ob diese Käufergruppe tatsächlich nur eine Erscheinung auf dem Bodenmarkt der neuen Bundesländer ist oder ob auch in den alten Bundesländern bereits deutliche Aktivitäten dieser Marktteilnehmer nachweisbar sind. Letztlich wurden die Probanden auch noch gefragt, ob die Politik die aktiven Landwirte beim Grundstücksverkehr im Vergleich zu Nichtlandwirten (noch) stärker schützen bzw. privilegieren sollte. Die Ergebnisse zeigen für die skizzierten Teilfragen jeweils ein sehr differenziertes Bild, wobei sich die Besonderheiten des ostdeutschen Bodenmarktes an vielen Stellen der Studie offenbart haben. Gleichwohl konnte auch verdeutlicht werden, dass die Rolle von außerlandwirtschaftlichen Investoren in den alten Bundesländern anscheinend größer ist als zunächst vermutet, wenngleich ihre Relevanz erwartungsgemäß geringer ist als in Ostdeutschland. Geeignete Kriterien zur Abgrenzung dieser Investorengruppe sind nach Aussage der Probanden u.a. die Berufsausbildung, die zukünftige Verwendung der Flächen, die Langfristigkeit des Engagements, der Transfer der Gewinne und die Ortsansässigkeit. Eine schärfere Reglementierung am Bodenmarkt wird von einem Großteil der befragten Landwirte favorisiert, wenngleich hieraus gesamtwirtschaftlich auch Nachteile resultieren könnten. Letzterer Punkt wird daher im abschließenden Kapital andiskutiert und erörtert

    Autonomous Exploration for 3D Map Learning

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    Abstract. Autonomous exploration is a frequently addressed problem in the ro-botics community. This paper presents an approach to mobile robot exploration that takes into account that the robot acts in the three-dimensional space. Our approach can build compact three-dimensional models autonomously and is able to deal with negative obstacles such as abysms. It applies a decision-theoretic framework which considers the uncertainty in the map to evaluate potential ac-tions. Thereby, it trades off the cost of executing an action with the expected information gain taking into account possible sensor measurements. We present experimental results obtained with a real robot and in simulation.

    High accuracy mobile robot positioning using external large volume metrology instruments

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    A method of accurately controlling the position of a mobile robot using an external large volume metrology (LVM) instrument is presented in this article. By utilising an LVM instrument such as a laser tracker or indoor GPS (iGPS) in mobile robot navigation, many of the most difficult problems in mobile robot navigation can be simplified or avoided. Using the real-time position information from the laser tracker, a very simple navigation algorithm, and a low cost robot, 5mm repeatability was achieved over a volume of 30m radius. A surface digitisation scan of a wind turbine blade section was also demonstrated, illustrating possible applications of the method for manufacturing processes. Further, iGPS guidance of a small KUKA omni-directional robot has been demonstrated, and a full scale prototype system is being developed in cooperation with KUKA Robotics, UK. © 2011 Taylor & Francis

    On the stability of high-speed milling with spindle speed variation

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    Spindle speed variation is a well-known technique to suppress regenerative machine tool vibrations, but it is usually considered to be effective only for low spindle speeds. In this paper, the effect of spindle speed variation is analyzed in the high-speed domain for spindle speeds corresponding to the first flip (period doubling) and to the first Hopf lobes. The optimal amplitudes and frequencies of the speed modulations are computed using the semidiscre- tization method. It is shown that period doubling chatter can effectively be suppressed by spindle speed variation, although, the technique is not effective for the quasiperiodic chatter above the Hopf lobe. The results are verified by cutting tests. Some special cases are also discussed where the practical behavior of the system differs from the predicted one in some ways. For these cases, it is pointed out that the concept of stability is understood on the scale of the principal period of the system—that is, the speed modulation period for variable spindle speed machining and the tooth passing period for constant spindle speed machining

    Ucma/GRP inhibits phosphate-induced vascular smooth muscle cell calcification via SMAD-dependent BMP signalling

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    Vascular calcification (VC) is the process of deposition of calcium phosphate crystals in the blood vessel wall, with a central role for vascular smooth muscle cells (VSMCs). VC is highly prevalent in chronic kidney disease (CKD) patients and thought, in part, to be induced by phosphate imbalance. The molecular mechanisms that regulate VC are not fully known. Here we propose a novel role for the mineralisation regulator Ucma/GRP (Upper zone of growth plate and Cartilage Matrix Associated protein/Gla Rich Protein) in phosphate-induced VSMC calcification. We show that Ucma/GRP is present in calcified atherosclerotic plaques and highly expressed in calcifying VSMCs in vitro. VSMCs from Ucma/GRP(-/-) mice showed increased mineralisation and expression of osteo/chondrogenic markers (BMP-2, Runx2, beta-catenin, p-SMAD1/5/8, ALP, OCN), and decreased expression of mineralisation inhibitor MGP, suggesting that Ucma/GRP is an inhibitor of mineralisation. Using BMP signalling inhibitor noggin and SMAD1/5/8 signalling inhibitor dorsomorphin we showed that Ucma/GRP is involved in inhibiting the BMP-2-SMAD1/5/8 osteo/chondrogenic signalling pathway in VSMCs treated with elevated phosphate concentrations. Additionally, we showed for the first time evidence of a direct interaction between Ucma/GRP and BMP-2. These results demonstrate an important role of Ucma/GRP in regulating osteo/chondrogenic differentiation and phosphate-induced mineralisation of VSMCs.NWO ZonMw [MKMD 40-42600-98-13007]; FCT [SFRH/BPD/70277/2010]info:eu-repo/semantics/publishedVersio

    Deconstructing the Late Phase of Vimentin Assembly by Total Internal Reflection Fluorescence Microscopy (TIRFM)

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    Quantitative imaging of intermediate filaments (IF) during the advanced phase of the assembly process is technically difficult, since the structures are several µm long and therefore they exceed the field of view of many electron (EM) or atomic force microscopy (AFM) techniques. Thereby quantitative studies become extremely laborious and time-consuming. To overcome these difficulties, we prepared fluorescently labeled vimentin for visualization by total internal reflection fluorescence microscopy (TIRFM). In order to investigate if the labeling influences the assembly properties of the protein, we first determined the association state of unlabeled vimentin mixed with increasing amounts of labeled vimentin under low ionic conditions by analytical ultracentrifugation. We found that bona fide tetrameric complexes were formed even when half of the vimentin was labeled. Moreover, we demonstrate by quantitative atomic force microscopy and electron microscopy that the morphology and the assembly properties of filaments were not affected when the fraction of labeled vimentin was below 10%. Using fast frame rates we observed the rapid deposition of fluorescently labeled IFs on glass supports by TIRFM in real time. By tracing their contours, we have calculated the persistence length of long immobilized vimentin IFs to 1 µm, a value that is identical to those determined for shorter unlabeled vimentin. These results indicate that the structural properties of the filaments were not affected significantly by the dye. Furthermore, in order to analyze the late elongation phase, we mixed long filaments containing either Alexa 488- or Alexa 647-labeled vimentin. The ‘patchy’ structure of the filaments obtained unambiguously showed the elongation of long IFs through direct end-to-end annealing of individual filaments

    Analyzing the regulation of metabolic pathways in human breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Tumor therapy mainly attacks the metabolism to interfere the tumor's anabolism and signaling of proliferative second messengers. However, the metabolic demands of different cancers are very heterogeneous and depend on their origin of tissue, age, gender and other clinical parameters. We investigated tumor specific regulation in the metabolism of breast cancer.</p> <p>Methods</p> <p>For this, we mapped gene expression data from microarrays onto the corresponding enzymes and their metabolic reaction network. We used Haar Wavelet transforms on optimally arranged grid representations of metabolic pathways as a pattern recognition method to detect orchestrated regulation of neighboring enzymes in the network. Significant combined expression patterns were used to select metabolic pathways showing shifted regulation of the aggressive tumors.</p> <p>Results</p> <p>Besides up-regulation for energy production and nucleotide anabolism, we found an interesting cellular switch in the interplay of biosynthesis of steroids and bile acids. The biosynthesis of steroids was up-regulated for estrogen synthesis which is needed for proliferative signaling in breast cancer. In turn, the decomposition of steroid precursors was blocked by down-regulation of the bile acid pathway.</p> <p>Conclusion</p> <p>We applied an intelligent pattern recognition method for analyzing the regulation of metabolism and elucidated substantial regulation of human breast cancer at the interplay of cholesterol biosynthesis and bile acid metabolism pointing to specific breast cancer treatment.</p
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