1,080 research outputs found

    Samenfeste Sorten oder Hybriden - Untersuchungen an Speisemöhren aus einem Anbauvergleich an zwei Standorten des Ökologischen Landbaus

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    An zwei Standorten des Ökologischen Landbaus (Neu-Eichenberg, Nordhessen: mittlerer bis schwerer Boden; Queck, Osthessen: leichter Boden) wurden Feldversuche mit Möhren durchgefĂŒhrt, um sechs samenfeste Sorten und sechs Hybriden auf ihre Anbautauglichkeit zu prĂŒfen. Außer der Roh- und HandelswarenertrĂ€ge wurden die Einheitlichkeit des Erntegutes (cv%) bestimmt und die Gehalte an Mineralstoffen (K, Ca, P, Mg) und Zuckern (D-Glucose, D-Fructose, Saccharose) analysiert. Auch sogenannte Bildschaffende Methoden (Kupferchloridkristallisation, Steigbild, Rundfilterchromatogramm) kamen zur Anwendung. Die untersuchten Hybriden erzielten MehrertrĂ€ge von 25 bis 29% und in den meisten FĂ€llen auch gleichmĂ€ĂŸiger lange RĂŒben als die Samenfesten. Die Inhaltsstoffuntersuchungen zeigten höhere Mineralstoffgehalte und niedrigere Quotienten von Mono- zu Disaccharide bei den samenfesten Sorten. Mithilfe der Bildschaffenden Methoden konnten die Proben blind klar in zwei unterschiedliche Gruppen differenziert werden: Die Bilder der samenfesten Sorten waren im Vergleich zu denjenigen der Hybriden geprĂ€gt durch einen höheren Grad an FormintensitĂ€t und Reife

    Samenfeste Sorten oder Hybriden - Anbauvergleich von Möhren unter den VerhĂ€ltnissen des Ökologischen Landbaus

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    A field trial with carrots was carried out in 1998 at two sites in Hesse (North: loamy soil in Neu-Eichenberg; East: sandy soil in Queck) to compare 6 open pollinating and 6 F1 hybrids under an Organic Farming regime. Characteristics of cultivation, harvest, quality, and longevity were measured. Of the parameters of cultivation and harvest the hybrids showed a more intensive foliage growth, higher marketable yields (plus 29 and 25%), and more homogeneous taproots than the open pollinating cultivars. Picture forming methods clearly separated the samples into the two groups of breeding methods. The open pollinating cultivars were characterized by higher degrees of form intensity and ripeness and a stable vitality. The hybrids of the sandy site had a better keeping quality after 6Âœ months storage, only the open pollinating cultivar ‘Rodelika’ had a very high ranking similar to the hybrids ‘Kardame F1’ and ‘Bolero F1’

    On the potential of augmented reality for mathematics teaching with the application cleARmaths

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    Learning content in mathematics, such as vector geometry, is still predominantly taught in an abstract manner, as the visualization and interaction of three-dimensional problems are limited with classical forms of teaching such as blackboard lessons or exercise sheets. This research article proposes the use of augmented reality (AR) in mathematics education. The proposed approach aims at easing the learning process related to vector geometry currently taught in senior mathematics classes by using intuitive visualization. The article introduces the concept of AR and presents the didactic foundations and the influence on the learning process based on an extensive literature review. Although studies see great potential in the use of AR for teaching mathematics, the method has so far hardly been used in schools. This can be mainly explained by the technological entry barrier of AR and the lack of simple, robust AR applications, in particular for vector geometry. To fill this gap, the authors developed “cleARmaths”, a developed android application for augmented reality-based teaching in vector geometry that allows widespread use. As a didactical concept, some example exercises sessions with the app are proposed, demonstrating how the app could be used in a mathematics classroom. Finally, the app was evaluated in a mathematics class and the results analyzed in a detailed study. It was found by the teacher and students to be beneficial and amusing, demonstrating the potential for AR in mathematics classes

    Semi- and Non-relativistic Limit of the Dirac Dynamics with External Fields

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    We show how to approximate Dirac dynamics for electronic initial states by semi- and non-relativistic dynamics. To leading order, these are generated by the semi- and non-relativistic Pauli hamiltonian where the kinetic energy is related to m2+Ο2\sqrt{m^2 + \xi^2} and Ο2/2m\xi^2 / 2m, respectively. Higher-order corrections can in principle be computed to any order in the small parameter v/c which is the ratio of typical speeds to the speed of light. Our results imply the dynamics for electronic and positronic states decouple to any order in v/c << 1. To decide whether to get semi- or non-relativistic effective dynamics, one needs to choose a scaling for the kinetic momentum operator. Then the effective dynamics are derived using space-adiabatic perturbation theory by Panati et. al with the novel input of a magnetic pseudodifferential calculus adapted to either the semi- or non-relativistic scaling.Comment: 42 page

    Dynamic and volumetric variables reliably predict fluid responsiveness in a porcine model with pleural effusion

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    Background: The ability of stroke volume variation (SVV), pulse pressure variation (PPV) and global end-diastolic volume (GEDV) for prediction of fluid responsiveness in presence of pleural effusion is unknown. The aim of the present study was to challenge the ability of SVV, PPV and GEDV to predict fluid responsiveness in a porcine model with pleural effusions. Methods: Pigs were studied at baseline and after fluid loading with 8 ml kg−1 6% hydroxyethyl starch. After withdrawal of 8 ml kg−1 blood and induction of pleural effusion up to 50 ml kg−1 on either side, measurements at baseline and after fluid loading were repeated. Cardiac output, stroke volume, central venous pressure (CVP) and pulmonary occlusion pressure (PAOP) were obtained by pulmonary thermodilution, whereas GEDV was determined by transpulmonary thermodilution. SVV and PPV were monitored continuously by pulse contour analysis. Results: Pleural effusion was associated with significant changes in lung compliance, peak airway pressure and stroke volume in both responders and non-responders. At baseline, SVV, PPV and GEDV reliably predicted fluid responsiveness (area under the curve 0.85 (p<0.001), 0.88 (p<0.001), 0.77 (p = 0.007). After induction of pleural effusion the ability of SVV, PPV and GEDV to predict fluid responsiveness was well preserved and also PAOP was predictive. Threshold values for SVV and PPV increased in presence of pleural effusion. Conclusions: In this porcine model, bilateral pleural effusion did not affect the ability of SVV, PPV and GEDV to predict fluid responsiveness

    Electron affinities of the first- and second- row atoms: benchmark ab initio and density functional calculations

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    A benchmark ab initio and density functional (DFT) study has been carried out on the electron affinities of the first- and second-row atoms. The ab initio study involves basis sets of spdfghspdfgh and spdfghispdfghi quality, extrapolations to the 1-particle basis set limit, and a combination of the CCSD(T), CCSDT, and full CI electron correlation methods. Scalar relativistic and spin-orbit coupling effects were taken into account. On average, the best ab initio results agree to better than 0.001 eV with the most recent experimental results. Correcting for imperfections in the CCSD(T) method improves the mean absolute error by an order of magnitude, while for accurate results on the second-row atoms inclusion of relativistic corrections is essential. The latter are significantly overestimated at the SCF level; for accurate spin-orbit splitting constants of second-row atoms inclusion of (2s,2p) correlation is essential. In the DFT calculations it is found that results for the 1st-row atoms are very sensitive to the exchange functional, while those for second-row atoms are rather more sensitive to the correlation functional. While the LYP correlation functional works best for first-row atoms, its PW91 counterpart appears to be preferable for second-row atoms. Among ``pure DFT'' (nonhybrid) functionals, G96PW91 (Gill 1996 exchange combined with Perdew-Wang 1991 correlation) puts in the best overall performance. The best results overall are obtained with the 1-parameter hybrid modified Perdew-Wang (mPW1) exchange functionals of Adamo and Barone [J. Chem. Phys. {\bf 108}, 664 (1998)], with mPW1LYP yielding the best results for first-row, and mPW1PW91 for second-row atoms. Indications exist that a hybrid of the type aa mPW1LYP + (1−a)(1-a) mPW1PW91 yields better results than either of the constituent functionals.Comment: Phys. Rev. A, in press (revised version, review of issues concerning DFT and electron affinities added

    Observation of two new Ξb−\Xi_b^- baryon resonances

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    Two structures are observed close to the kinematic threshold in the Ξb0π−\Xi_b^0 \pi^- mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1^{-1} recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content bdsbds are expected in this mass region: the spin-parity JP=12+J^P = \frac{1}{2}^+ and JP=32+J^P=\frac{3}{2}^+ states, denoted Ξbâ€Č−\Xi_b^{\prime -} and Ξb∗−\Xi_b^{*-}. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be m(Ξbâ€Č−)−m(Ξb0)−m(π−)=3.653±0.018±0.006m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006 MeV/c2/c^2, m(Ξb∗−)−m(Ξb0)−m(π−)=23.96±0.12±0.06m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06 MeV/c2/c^2, Γ(Ξb∗−)=1.65±0.31±0.10\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10 MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of Γ(Ξbâ€Č−)<0.08\Gamma(\Xi_b^{\prime -}) < 0.08 MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

    Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at √s=7 TeV

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    Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the form of an enhancement of pairs of like-sign charged pions with small four-momentum difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source is investigated, determining both the correlation radius and the chaoticity parameter. The measured correlation radius is found to increase as a function of increasing charged-particle multiplicity, while the chaoticity parameter is seen to decreas
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