656 research outputs found

    A Brief Survey of Recent Edge-Preserving Smoothers

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    We introduce recent and very recent smoothing methods and discuss them in the common framework of `energy functions'. Focus is on the preservation of boundaries, spikes and canyons in presence of noise

    Long-term evolution of 1991 DA: A dynamically evolved extinct Halley-type comet

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    The long-term dynamical evolution of 21 variational orbits for the intermediate-period asteroid 1991 DA was followed for up to +/-10(exp 5) years from the present. 1991 DA is close to the 2:7 resonance with Jupiter; it has avoided close encounters, within 1 AU, with this planet for at least the past 30,000 years, even at the node crossing. The future evolution typically shows no close encounters with Jupiter within at least 50,000 years. This corresponds to the mean time between node crossings with either Jupiter or Saturn. Close encounters with Saturn and Jupiter lead to a chaotic evolution for the whole ensemble, while secular perturbations cause large-amplitude swings in eccentricity and inclination (the latter covering the range 15 deg approximately less than i approximately less than 85 deg) which correlate with deep excursions of the perihelion distance to values much less than 1 AU. These variations are similar to those found in P/Machholz and a variety of other high-inclination orbits, e.g., P/Hartley-IRAS. We emphasize the connection between the orbital evolution of 1991 DA and that of Halley-type comets. If 1991 DA was once a comet, it is not surprising that it is now extinct

    Efficient Teleportation between Remote Single-Atom Quantum Memories

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    We demonstrate teleportation of quantum bits between two single atoms in distant laboratories. Using a time-resolved photonic Bell-state measurement, we achieve a teleportation fidelity of (88.0+/-1.5)%, largely determined by our entanglement fidelity. The low photon collection efficiency in free space is overcome by trapping each atom in an optical cavity. The resulting success probability of 0.1% is almost 5 orders of magnitude larger than in previous experiments with remote material qubits. It is mainly limited by photon propagation and detection losses and can be enhanced with a cavity-based deterministic Bell-state measurement.Comment: 7 pages, 4 figures, 1 tabl

    Generation of single photons from an atom-cavity system

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    A single rubidium atom trapped within a high-finesse optical cavity is an efficient source of single photons. We theoretically and experimentally study single-photon generation using a vacuum stimulated Raman adiabatic passage. We experimentally achieve photon generation efficiencies of up to 34% and 56% on the D1 and D2 line, respectively. Output coupling with 89% results in record-high efficiencies for single photons in one spatiotemporally well-defined propagating mode. We demonstrate that the observed generation efficiencies are constant in a wide range of applied pump laser powers and virtual level detunings. This allows for independent control over the frequency and wave packet envelope of the photons without loss in efficiency. In combination with the long trapping time of the atom in the cavity, our system constitutes a significant advancement toward an on-demand, highly efficient single-photon source for quantum information processing tasks.Comment: 7 pages, 5 figure

    Organic diets with alfalfa silage for laying hens: Egg quality

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    Laying hens were fed with organic diets containing chopped, extruded or pelleted alfalfa silage and the quality of the eggs was evaluated. Four groups were conformed: a control group (A) fed with a complete feed mixture (CFM) and three silage groups (B, C and D) fed with a supplementary feed mixture (SFM). The SFM was formulated based on an assumed ingestion of 20 % silage and rapeseed oil was used as energy source. Before ensiling, the alfalfa was chopped (B) and additionally extruded (C). One half of the extruded silage was pelleted together with the SFM to produce the pelletized silage (D). Eggs from hens fed with silage (B, C and D) contained 2.4 times more n-3 fatty acids than A. The thermally treated silage (C and D) produced higher concentrations of saturated fatty acids. B and C (high rapeseed oil intakes) showed the highest monounsaturated fatty acids. In spite of the high fat intake, their cholesterol levels were similar to A (A: 12.4; B: 12.3; C: 12.6 mg/g yolk; p > 0.05) due to the anti-cholesterolemic effect of the alfalfa. D consumed the lowest amount of fat but the highest amount of silage, corresponding to the lowest cholesterol level. The fat consumed was essential in the absorption of carotenoids. Thus, yolks from the silage groups showed decreasing values for the intensity of red and yellow colour as the intake in terms of the amount of fat/silage decreased

    Veränderungen der Fleischqualität durch den Einsatz von Luzernesilage in der ökologischen Broilermast

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    In a feeding trial broilers were fed with chopped, extruded and pelletized silage from young harvested alfalfa. The broilers consumed up to 30 % of silage of their total dry matter intake. In comparison to the control group that was fed with a complete feed mixture, the meat of the silage groups showed a higher percentage of poly unsaturated fatty acids, a reduced cholesterol content and an intensive yellow colour. The sensory characteristics were not influenced. With regard to the human nutrition these changes in meat quality are desirable. Alfalfa silage can be used deliberately to produce broiler meat with positive and healthy properties, and consequently as a marketing argument

    Noise Reduction in Images: Some Recent Edge-Preserving Methods

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    We introduce some recent and very recent smoothing methods which focus on the preservation of boundaries, spikes and canyons in presence of noise. We try to point out basic principles they have in common; the most important one is the robustness aspect. It is reflected by the use of `cup functions' in the statistical loss functions instead of squares; such cup functions were introduced early in robust statistics to down weight outliers. Basically, they are variants of truncated squares. We discuss all the methods in the common framework of `energy functions', i.e we associate to (most of) the algorithms a `loss function' in such a fashion that the output of the algorithm or the `estimate' is a global or local minimum of this loss function. The third aspect we pursue is the correspondence between loss functions and their local minima and nonlinear filters. We shall argue that the nonlinear filters can be interpreted as variants of gradient descent on the loss functions. This way we can show that some (robust) M-estimators and some nonlinear filters produce almost the same result
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