Quantum state reconstruction with imperfect rotations on an inhomogeneously broadened ensemble of qubits

We present a method for performing quantum state reconstruction on qubits and qubit registers in the presence of decoherence and inhomogeneous broadening. The method assumes only rudimentary single qubit rotations as well as knowledge of decoherence and loss mechanisms. We show that full state reconstruction is possible even in the case where single qubit rotations may only be performed imperfectly. Furthermore we show that for ensemble quantum computing proposals, quantum state reconstruction is possible even if the ensemble experiences inhomogeneous broadening and if only imperfect qubit manipulations are available during state preparation and reconstruction.Comment: 6 pages, 5 figure

Frequency, type, and distribution of EST-SSRs from three genotypes of Lolium perenne, and their conservation across orthologous sequences of Festuca arundinacea, Brachypodium distachyon, and Oryza sativa

<p>Abstract</p> <p>Background</p> <p>Simple sequence repeat (SSR) markers are highly informative and widely used for genetic and breeding studies in several plant species. They are used for cultivar identification, variety protection, as anchor markers in genetic mapping, and in marker-assisted breeding. Currently, a limited number of SSR markers are publicly available for perennial ryegrass (<it>Lolium perenne</it>). We report on the exploitation of a comprehensive EST collection in <it>L. perenne </it>for SSR identification. The objectives of this study were 1) to analyse the frequency, type, and distribution of SSR motifs in ESTs derived from three genotypes of <it>L. perenne</it>, 2) to perform a comparative analysis of SSR motif polymorphisms between allelic sequences, 3) to conduct a comparative analysis of SSR motif polymorphisms between orthologous sequences of <it>L. perenne</it>, <it>Festuca arundinacea, Brachypodium distachyon</it>, and <it>O. sativa</it>, 4) to identify functionally associated EST-SSR markers for application in comparative genomics and breeding.</p> <p>Results</p> <p>From 25,744 ESTs, representing 8.53 megabases of nucleotide information from three genotypes of <it>L. perenne</it>, 1,458 ESTs (5.7%) contained one or more SSRs. Of these SSRs, 955 (3.7%) were non-redundant. Tri-nucleotide repeats were the most abundant type of repeats followed by di- and tetra-nucleotide repeats. The EST-SSRs from the three genotypes were analysed for allelic- and/or genotypic SSR motif polymorphisms. Most of the SSR motifs (97.7%) showed no polymorphisms, whereas 22 EST-SSRs showed allelic- and/or genotypic polymorphisms. All polymorphisms identified were changes in the number of repeat units. Comparative analysis of the <it>L. perenne </it>EST-SSRs with sequences of <it>Festuca arundinacea</it>, <it>Brachypodium distachyon</it>, and <it>Oryza sativa </it>identified 19 clusters of orthologous sequences between these four species. Analysis of the clusters showed that the SSR motif generally is conserved in the closely related species <it>F. arundinacea</it>, but often differs in length of the SSR motif. In contrast, SSR motifs are often lost in the more distant related species <it>B. distachyon </it>and <it>O. sativa</it>.</p> <p>Conclusion</p> <p>The results indicate that the <it>L. perenne </it>EST-SSR markers are a valuable resource for genetic mapping, as well as evaluation of co-location between QTLs and functionally associated markers.</p

Seasonal changes in brain serotonin transporter binding in short 5-HTTLPR-allele carriers but not in long-allele homozygotes

Several findings suggest seasonal variations in the serotonin (5-HT) system. We sought evidence for seasonal variation in the serotonin transporter (5-HTT). We found that length of daylight time in minutes correlates negatively with 5-HTT binding in the putamen and the caudate, with a similar tendency in the thalamus, but no such association in the midbrain. In the putamen, an anatomical region with a dense serotonin innervation that is implicated in processing of aversive stimuli, we found a significant gene*daylight effect with a negative correlation between the 5-HTT binding and daylight time in carriers of the short 5-HTTLPR allele, but not in carriers of the long allele. The neurobiological endophenotype identified here directly links activation studies, showing responses on the neural circuit level, with dynamic changes in transporter expression measured in vivo

Health Assessment and Seroepidemiologic Survey of Potential Pathogens in Wild Antillean Manatees (Trichechus manatus manatus)

The Antillean manatee (Trichechus manatus manatus), a subspecies of the West Indian manatee, inhabits fresh, brackish, and warm coastal waters distributed along the eastern border of Central America, the northern coast of South America, and throughout the Wider Caribbean Region. Threatened primarily by human encroachment, poaching, and habitat degradation, Antillean manatees are listed as endangered by the International Union for the Conservation of Nature. The impact of disease on population viability remains unknown in spite of concerns surrounding the species' ability to rebound from a population crash should an epizootic occur. To gain insight on the baseline health of this subspecies, a total of 191 blood samples were collected opportunistically from wild Antillean manatees in Belize between 1997 and 2009. Hematologic and biochemical reference intervals were established, and antibody prevalence to eight pathogens with zoonotic potential was determined. Age was found to be a significant factor of variation in mean blood values, whereas sex, capture site, and season contributed less to overall differences in parameter values. Negative antibody titers were reported for all pathogens surveyed except for Leptospira bratislava, L. canicola, and L. icterohemorrhagiae, Toxoplasma gondii, and morbillivirus. As part of comprehensive health assessment in manatees from Belize, this study will serve as a benchmark aiding in early disease detection and in the discernment of important epidemiologic patterns in the manatees of this region. Additionally, it will provide some of the initial tools to explore the broader application of manatees as sentinel species of nearshore ecosystem health

Loschmidt echo for local perturbations: non-monotonous cross-over from the Fermi-golden-rule to the escape-rate regime

We address the sensitivity of quantum mechanical time evolution by considering the time decay of the Loschmidt echo (LE) (or fidelity) for local perturbations of the Hamiltonian. Within a semiclassical approach we derive analytical expressions for the LE decay for chaotic systems for the whole range from weak to strong local perturbations and identify different decay regimes which complement those known for the case of global perturbations. For weak perturbations a Fermi-golden-rule (FGR) type behavior is recovered. For strong perturbations the escape-rate regime is reached, where the LE decays exponentially with a rate independent of the perturbation strength. The transition between the FGR regime and the escape-rate regime is non-monotonic, i.e. the rate of the exponential time-decay of the LE oscillates as a function of the perturbation strength. We further perform extensive quantum mechanical calculations of the LE based on numerical wave packet evolution which strongly support our semiclassical theory. Finally, we discuss in some detail possible experimental realizations for observing the predicted behavior of the LE.Comment: 27 pages, 7 figures; important changes throughout the pape