2,569 research outputs found
The Use of Cafeteria Trials for the Selection of \u3ci\u3eDesmodium ovalifolium\u3c/i\u3e Genotypes
For the selection of tropical legumes which contain anti-nutritive components such as tannins, relative acceptability of genotypes to ruminants is of particular importance, since these plant components may influence selective grazing behaviour and subsequent animal productivity. Plant-animal interactions are not predictable from laboratory analyses. Involving grazing animals through the conduction of relative-acceptability (=cafeteria) trials at early stages of the germplasm selection process might therefore provide a convenient tool to adjust and confirm genotype selection based on laboratory quality analyses data. As part of a multilocational germplasm evaluation project, cafeteria-experiments were conducted at two contrasting environments in Colombia with a core collection of Desmodium ovalifolium, a tropical legume species containing tannins. The objective of these experiments was to assess the usefulness of such acceptability trials in the selection of D. ovalifolium genotypes. Relative acceptability indices for the 18 accessions confirm genotype selection based on a series of laboratory quality analyses during earlier stages of the project and indicate pronounced genotype-environment interactions. Moreover, animal activity profiles confirm the influence of plant-environment-animal interactions and thus the usefulness of cafeteriatrials for germplasm selection projects
Anomalous Periodicity of the Current-Phase Relationship of Grain-Boundary Josephson Junctions in High-Tc Superconductors
The current-phase relation (CPR) for asymmetric 45 degree Josephson junctions
between two d-wave superconductors has been predicted to exhibit an anomalous
periodicity. We have used the single-junction interferometer to investigate the
CPR for this kind of junctions in YBCO thin films. Half-fluxon periodicity has
been experimentally found, providing a novel source of evidence for the d-wave
symmetry of the pairing state of the cuprates.Comment: 4 pages, 5 figure
The direct evaluation of attosecond chirp from a streaking measurement
We derive an analytical expression, from classical electron trajectories in a
laser field, that relates the breadth of a streaked photoelectron spectrum to
the group-delay dispersion of an isolated attosecond pulse. Based on this
analytical expression, we introduce a simple, efficient and robust procedure to
instantly extract the attosecond pulse's chirp from the streaking measurement.Comment: 4 figure
Coherent control for the spherical symmetric box potential in short and intensive XUV laser fields
Coherent control calculations are presented for a spherically symmetric box
potential for non-resonant two photon transition probabilities. With the help
of a genetic algorithm (GA) the population of the excited states are maximized
and minimized. The external driving field is a superposition of three intensive
extreme ultraviolet (XUV) linearly polarized laser pulses with different
frequencies in the femtosecond duration range. We solved the quantum mechanical
problem within the dipole approximation. Our investigation clearly shows that
the dynamics of the electron current has a strong correlation with the
optimized and neutralizing pulse shape.Comment: 11 Pages 3 Figure
Tema Con Variazioni: Quantum Channel Capacity
Channel capacity describes the size of the nearly ideal channels, which can
be obtained from many uses of a given channel, using an optimal error
correcting code. In this paper we collect and compare minor and major
variations in the mathematically precise statements of this idea which have
been put forward in the literature. We show that all the variations considered
lead to equivalent capacity definitions. In particular, it makes no difference
whether one requires mean or maximal errors to go to zero, and it makes no
difference whether errors are required to vanish for any sequence of block
sizes compatible with the rate, or only for one infinite sequence.Comment: 32 pages, uses iopart.cl
Economic space: On the analysis and interpretation of pottery production and distribution
Ceramics are particularly well suited for investigating general patterns of the distribution of premodern products. Archaeometric methods, used to determine raw materials and production techniques, permit the identification of places of production. The work of the research group presented here pursues two objectives: (i) to investigate the usefulness of portable X-ray fluorescence equipment for the analysis of ceramics and (ii) to identify, interpret and study distribution areas of ceramic products in comparative prospective. The paper discusses key economic concepts, sets out the archaeometric methodology and presents initial results in the context of two examples
Parallel Measurement and Modeling of Transport in the Darht II Beamline on ETA II
To successfully tune the DARHT II transport beamline requires the close coupling of a model of the beam transport and the measurement of the beam observables as the beam conditions and magnet settings are varied. For the ETA II experiment using the DARHT II beamline components this was achieved using the SUICIDE (Simple User Interface Connecting to an Integrated Data Environment) data analysis environment and the FITS (Fully Integrated Transport Simulation) model. The SUICIDE environment has direct access to the experimental beam transport data at acquisition and the FITS predictions of the transport for immediate comparison. The FITS model is coupled into the control system where it can read magnet current settings for real time modeling. We find this integrated coupling is essential for model verification and the successful development of a tuning aid for the efficient convergence on a useable tune. We show the real time comparisons of simulation and experiment and explore the successes and limitations of this close coupled approach
Entropy and Quantum Kolmogorov Complexity: A Quantum Brudno's Theorem
In classical information theory, entropy rate and Kolmogorov complexity per
symbol are related by a theorem of Brudno. In this paper, we prove a quantum
version of this theorem, connecting the von Neumann entropy rate and two
notions of quantum Kolmogorov complexity, both based on the shortest qubit
descriptions of qubit strings that, run by a universal quantum Turing machine,
reproduce them as outputs.Comment: 26 pages, no figures. Reference to publication added: published in
the Communications in Mathematical Physics
(http://www.springerlink.com/content/1432-0916/
- …