269 research outputs found
Time-optimal universal quantum gates on superconducting circuits
Decoherence is inevitable when manipulating quantum systems. It decreases the
quality of quantum manipulations and thus is one of the main obstacles for
large-scale quantum computation, where high-fidelity quantum gates are needed.
Generally, the longer a gate operation is, the more decoherence-induced gate
infidelity will be. Therefore, how to shorten the gate time becomes an urgent
problem to be solved. To this end, time-optimal control based on solving the
quantum brachistochrone equation is a straightforward solution. Here, based on
time-optimal control, we propose a scheme to realize universal quantum gates on
superconducting qubits in a two-dimensional square lattice configuration, and
the two-qubit gate fidelity approaches 99.9\%. Meanwhile, we can further
accelerate the Z-axis gate considerably by adjusting the detuning of the
external driving. Finally, in order to reduce the influence of the dephasing
error, decoherence-free subspace encoding is also incorporated in our physical
implementation. Therefore, we present a fast quantum scheme which is promising
for large-scale quantum computation.Comment: v2 accepte
A genome scan for quantitative trait loci affecting growth-related traits in an F1 family of Asian seabass (Lates calcarifer)
BACKGROUND: Body weight and length are economically important traits in foodfish species influenced by quantitative trait loci (QTL) and environmental factors. It is usually difficult to dissect the genetic and environmental effects. Asian seabass (Lates calcarifer) is an important marine foodfish species with a compact genome (~700 Mb). The recent construction of a first generation linkage map of Asian seabass with 240 microsatellites provides a good opportunity to determine the number and position of QTL, and the magnitude of QTL effects with a genome scan. RESULTS: We conducted a genome scan for QTL affecting body weight, standard length and condition factors in an F1 family containing 380 full-sib individuals from a breeding stock by using 97 microsatellites evenly covering 24 chromosomes. Interval mapping and multiple QTL model mapping detected five significant and 27 suggestive QTL on ten linkage groups (LGs). Among the five significant QTL detected, three (qBW2-a, qTL2-a and qSL2-a) controlling body weight, total and standard length respectively, were mapped on the same region near Lca287 on LG2, and explained 28.8, 58.9 and 59.7% of the phenotypic variance. The other two QTL affecting body weight, qBW2-b and qBW3, were located on LG2 and 3, and accounted for 6.4 and 8.8% of the phenotypic variance. Suggestive QTL associated with condition factors are located on six different LGs. CONCLUSION: This study presents the first example of QTL detection for growth-related traits in an F1 family of a marine foodfish species. The results presented here will enable further fine-mapping of these QTL for marker-assisted selection of the Asian seabass, eventually identifying individual genes responsible for growth-related traits
A simple and efficient method for isolating polymorphic microsatellites from cDNA
<p>Abstract</p> <p>Background</p> <p>Microsatellites in cDNA are useful as molecular markers because they represent transcribed genes and can be used as anchor markers for linkage and comparative mapping, as well as for studying genome evolution. Microsatellites in cDNA can be detected in existing ESTs by data mining. However, in most fish species, no ESTs are available or the number of ESTs is limited, although fishes represent half of the vertebrates on the earth. We developed a simple and efficient method for isolation of microsatellites from cDNA in fish.</p> <p>Results</p> <p>The method included normalization of 150 ng cDNA using 0.5 U duplex-specific nuclease (DSN) at 65°C for 30 min, enrichment of microsatellites using biotinylated oligonucleotides and magnetic field, and directional cloning of cDNA into a vector. We tested this method to enrich CA- and GA-microsatellites from cDNA of Asian seabass, and demonstrated that enrichment of microsatellites from normalized cDNA could increased the efficiency of microsatellite isolation over 30 times as compared to direct sequencing of clones from cDNA libraries. One hundred and thirty-nine (36.2%) out of 384 clones from normalized cDNA contained microsatellites. Unique microsatellite sequences accounted for 23.6% (91/384) of sequenced clones. Sixty microsatellites isolated from cDNA were characterized, and 41 were polymorphic. The average allele number of the 41 microsatellites was 4.85 ± 0.54, while the expected heterozygosity was 0.56 ± 0.03. All the isolated microsatellites inherited in a Mendelian pattern.</p> <p>Conclusion</p> <p>Normalization of cDNA substantially increased the efficiency of enrichment of microsatellites from cDNA. The described method for isolation of microsatellites from cDNA has the potential to be applied to a wide range of fish species. The microsatellites isolated from cDNA could be useful for linkage and comparative mapping, as well as for studying genome evolution.</p
Three-dimensional potential energy surface for fission of U within covariant density functional theory
We have calculated the three-dimensional potential energy surface (PES) for
the fission of compound nucleus U using the covariant density
functional theory with constraints on the axial quadrupole and octupole
deformations as well as the nucleon number in the neck
. By considering the additonal degree of freedom , coexistence of the
elongated and compact fission modes is predicted for . Remarkably, the PES becomes very shallow across a large range of
quadrupole and octupole deformations for small , and consequently, the
scission line in plane will extend to a shallow band,
which leads to a fluctuation for the estimated total kinetic energies by
several to ten MeV and for the fragment masses by several to about ten
nucleons
Colorful Hydrophobic Poly(Vinyl Butyral)/Cationic Dye Fibrous Membranes via a Colored Solution Electrospinning Process
Supplementary Materials. (DOCX 3474Â kb
Relationship between low-density lipoprotein levels on admission and 1-year outcome in patients with acute ST-segment-elevation myocardial infarction
AbstractThis study assessed the relationship between low-density lipoprotein cholesterol (LDL-C) levels on admission and the incidence of major adverse cardiovascular events (MACE) in patients with acute ST-segment-elevation myocardial infarction (ASTEMI). Patients with ASTEMI who had a lipid profile tested within 24 hours of symptom onset were enrolled. They were stratified into high and low LDL-C groups according to whether their LDL-C was above (n = 501) or below (n = 575) the median level, respectively. The incidence of MACE, cardiovascular death, non-fatal MI, revascularization, and stroke was compared between the groups at 1 month, 6 months, and 1 year. Survival analysis and Cox proportional hazard analysis were performed. In-hospital use of beta blockers was better in the high than in the low LDL-C group (76.6% vs. 69.7%, p = 0.01). Statin use was significantly higher in the high than in the low LDL-C group during follow-up (86.8% vs. 80.0%, p = 0.003 at1 month; 71.6% vs. 62.4%, p = 0.002 at 6 months; 67.8% vs. 61.2%, p = 0.03 at 1 year). The incidence of MACE on follow-up at 1 month was higher in the low than in the high LDL-C group (12.0% vs. 8.1%, p = 0.04). At 1 year, survival was not significantly different between the groups. Cox proportional hazards analysis indicated that the incidence of MACE was significantly associated with hypertension, current smoking, high-density lipoprotein cholesterol (HDL-C), in-hospital use of beta blockers, and statin use on follow-up (p < 0.01). LDL-C levels on admission in patients with ASTEMI had no significant effect on the 6-month and 1-year incidence of MACE, but the incidence of MACE was significantly higher in the low LDL-C group at 1 month. It would be relevant to further investigate the HDL-C level on admission, in-hospital use of beta blockers, and statin use during follow-up in relation to MACE
Construction of a BAC library and mapping BAC clones to the linkage map of Barramundi, Lates calcarifer
<p>Abstract</p> <p>Background</p> <p>Barramundi (<it>Lates calcarifer</it>) is an important farmed marine food fish species. Its first generation linkage map has been applied to map QTL for growth traits. To identify genes located in QTL responsible for specific traits, genomic large insert libraries are of crucial importance. We reported herein a bacterial artificial chromosome (BAC) library and the mapping of BAC clones to the linkage map.</p> <p>Results</p> <p>This BAC library consisted of 49,152 clones with an average insert size of 98 kb, representing 6.9-fold haploid genome coverage. Screening the library with 24 microsatellites and 15 ESTs/genes demonstrated that the library had good genome coverage. In addition, 62 novel microsatellites each isolated from 62 BAC clones were mapped onto the first generation linkage map. A total of 86 BAC clones were anchored on the linkage map with at least one BAC clone on each linkage group.</p> <p>Conclusion</p> <p>We have constructed the first BAC library for <it>L. calcarifer </it>and mapped 86 BAC clones to the first generation linkage map. This BAC library and the improved linkage map with 302 DNA markers not only supply an indispensable tool to the integration of physical and linkage maps, the fine mapping of QTL and map based cloning genes located in QTL of commercial importance, but also contribute to comparative genomic studies and eventually whole genome sequencing.</p
Diagnosis of benign and malignant nodules with a radiomics model integrating features from nodules and mammary regions on DCE-MRI
ObjectivesTo establish a radiomics model for distinguishing between the benign and malignant mammary gland nodules via combining the features from nodule and mammary regions on DCE-MRIMethodsIn this retrospective study, a total of 103 cases with mammary gland nodules (malignant/benign = 80/23) underwent DCE-MRI, and was confirmed by biopsy pathology. Features were extracted from both nodule region and mammary region on DCE-MRI. Three SVM classifiers were built for diagnosis of benign and malignant nodules as follows: the model with the features only from nodule region (N model), with the features only from mammary region (M model) and the model combining the features from nodule region and mammary region (NM model). The performance of models was evaluated with the area under the curve of receiver operating characteristic (AUC).ResultsOne radiomic features is selected from nodule region and 3 radiomic features is selected from mammary region. Compared with N or M model, NM model exhibited the best performance with an AUC of 0.756.ConclusionsCompared with the model only using the features from nodule or mammary region, the radiomics-based model combining the features from nodule and mammary region outperformed in the diagnosis of benign and malignant nodules
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