658 research outputs found
A Brief Survey of Recent Edge-Preserving Smoothers
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
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
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
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
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
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
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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