5,489 research outputs found
Fundamental Cycles and Graph Embeddings
In this paper we present a new Good Characterization of maximum genus of a
graph which makes a common generalization of the works of Xuong, Liu, and Fu et
al. Based on this, we find a new polynomially bounded algorithm to find the
maximum genus of a graph
Beating the Clauser-Horne-Shimony-Holt and the Svetlichny games with Optimal States
We study the relation between the maximal violation of Svetlichny's
inequality and the mixedness of quantum states and obtain the optimal state
(i.e., maximally nonlocal mixed states, or MNMS, for each value of linear
entropy) to beat the Clauser-Horne-Shimony-Holt and the Svetlichny games. For
the two-qubit and three-qubit MNMS, we showed that these states are also the
most tolerant state against white noise, and thus serve as valuable quantum
resources for such games. In particular, the quantum prediction of the MNMS
decreases as the linear entropy increases, and then ceases to be nonlocal when
the linear entropy reaches the critical points and for the
two- and three-qubit cases, respectively. The MNMS are related to classical
errors in experimental preparation of maximally entangled states.Comment: 7 pages, 3 figures; minor changes; accepted in Physical Review
Nano-Size Layered Manganese-Calcium Oxide as an Efficient and Biomimetic Catalyst for Water Oxidation Under Acidic Conditions: Comparable To Platinum
Inspired by Nature's catalyst, a nano-size layered manganese-calcium oxide showed a low overvoltage for water oxidation in acidic solutions, which is comparable to platinum.Institute for Advanced Studies in Basic Sciences and the National Elite FoundationUS Department of Energy, Office of Basic Energy Sciences, Division of Chemical, Geochemical and Biological Sciences DE-FG02-86ER13622, DE-FG0209ER16119Russian Foundation for Basic Research 11-04-01389a, 12-0492101a, 13-04-92711aMolecular and Cell Biology Programs of the Russian Academy of SciencesCenter for Electrochemistr
Gate-tuned normal and superconducting transport at the surface of a topological insulator
Three-dimensional topological insulators are characterized by the presence of
a bandgap in their bulk and gapless Dirac fermions at their surfaces. New
physical phenomena originating from the presence of the Dirac fermions are
predicted to occur, and to be experimentally accessible via transport
measurements in suitably designed electronic devices. Here we study transport
through superconducting junctions fabricated on thin Bi2Se3 single crystals,
equipped with a gate electrode. In the presence of perpendicular magnetic field
B, sweeping the gate voltage enables us to observe the filling of the Dirac
fermion Landau levels, whose character evolves continuously from electron- to
hole-like. When B=0, a supercurrent appears, whose magnitude can be gate tuned,
and is minimum at the charge neutrality point determined from the Landau level
filling. Our results demonstrate how gated nano-electronic devices give control
over normal and superconducting transport of Dirac fermions at an individual
surface of a three-dimensional topological insulator.Comment: 28 pages, 5 figure
A new measles mumps rubella (MMR) vaccine: a randomized comparative trial for assessing the reactogenicity and immunogenicity of three consecutive production lots and comparison with a widely used MMR vaccine in measles primed children
AbstractObjectives: A multicenter, single-blind, randomized, controlled clinical study was conducted in healthy 15–18-month-old children in order to assess the immunogenicity and reactogenicity of three consecutive lots of a new measles-mumps-rubella (MMR) vaccine, GSK MMR.Design: A total of 500 enrolled subjects were randomized into four groups to receive either a single dose of one of the three lots of GSK MMR (three groups — 125 subjects in each group) or Merck MMR vaccine (125 subjects). Once clinical consistency had been demonstrated, the data were pooled and compared with the widely used Merck vaccine. Solicited local and general symptoms were recorded using diary cards, and antibody levels were determined using ELISA assays.Results: No differences in the incidence of local and general symptoms or seroconversion rates were seen in the groups receiving different lots of GSK MMR. Compared with Merck MMR, there was a significantly lower incidence of local pain (P<0.001) and swelling (P=0.038) in infants receiving the GSK MMR vaccine. The incidences of all other solicited local and general symptoms were comparable between the two groups. No signs of suspected meningitis were reported. No serious adverse events were reported by the investigator to be related to vaccination. Equivalent seroconversion rates and post-vaccination GMTs were observed in the groups receiving the two MMR vaccines. In conclusion, the new GSK MMR vaccine administered in measles-primed children demonstrated satisfactory immunogenicity and safety profiles as good as the Merck MMR vaccine
Bridgeness: A Local Index on Edge Significance in Maintaining Global Connectivity
Edges in a network can be divided into two kinds according to their different
roles: some enhance the locality like the ones inside a cluster while others
contribute to the global connectivity like the ones connecting two clusters. A
recent study by Onnela et al uncovered the weak ties effects in mobile
communication. In this article, we provide complementary results on document
networks, that is, the edges connecting less similar nodes in content are more
significant in maintaining the global connectivity. We propose an index named
bridgeness to quantify the edge significance in maintaining connectivity, which
only depends on local information of network topology. We compare the
bridgeness with content similarity and some other structural indices according
to an edge percolation process. Experimental results on document networks show
that the bridgeness outperforms content similarity in characterizing the edge
significance. Furthermore, extensive numerical results on disparate networks
indicate that the bridgeness is also better than some well-known indices on
edge significance, including the Jaccard coefficient, degree product and
betweenness centrality.Comment: 10 pages, 4 figures, 1 tabl
Microsatellite-based Genetic Diversity and Evolutionary Relationships of Six Dog Breeds
The Tibetan Mastiff is one of the most archaic, ferocious and the largest dogs in the world. The Kunming dog is the chief working-dog breed in China. In this study, ten microsatellite loci were used to assess the genetic diversity and evolutionary relationships in six dog breeds, including Tibetan Mastiff, Kunming dog, Belgian Malinois, Labrador Retriever, English Springer Spaniel, and German Shepherd. The highest genetic diversity was exhibited by the Tibetan Mastiff, indicating useful protection and little inbreeding in the modern Tibetan Mastiff. Higher genetic diversity was observed in European breeds, supporting the hypotheses that breeders outcross their pure breed dogs occasionally to avoid deleterious effects in Europe. Evolutionary relationships showed that English Springer Spaniel and Labrador Retriever were clustered together, then with the Tibetan Mastiff, consistent with previous cluster results. German Shepherd and Kunming dog were grouped together, coinciding with the breeding history of Kunming dog. It is the first time that Tibetan Mastiff and Kunming dog have been analyzed with microsatellites
Characterization of biogenic primary and secondary organic aerosols in the marine atmosphere over the East China Sea
Molecular composition and abundance of sugars and secondary organic aerosols
(SOA) from biogenic sources over the East China Sea were investigated based
on gas chromatography–mass spectrometry. Biogenic SOA tracers and sugars
exhibit higher levels in the samples affected by continental air masses,
demonstrating the terrestrial outflows of organic matter to the East China
Sea. Glucose was the dominant sugar species (0.31–209, 18.8 ng m−3), followed by mannitol – a fungal spore tracer. All sugar compounds
show generally higher average concentrations in the nighttime than in the
daytime. 3-Methyl-1,2,3-butanetricarboxylic acid, one higher generation
photooxidation tracer of monoterpene SOA, was found to be the most abundant
species among measured biogenic SOA markers, suggesting the input of aged
organic aerosols through long-range transport. Fungal-spore-derived organic
carbon (OC) was the biggest contributor to total OC (0.03 %–19.8 %,
3.1 %), followed by sesquiterpene-derived secondary OC (SOC),
biomass-burning-derived OC, and monoterpene- and isoprene-derived SOC. Larger
carbon percentages of biogenic primary OCs and SOCs in total OC presented in
the terrestrially influenced aerosols indicate significant contributions of
continental aerosols through long-range transport. Positive matrix
factorization results illustrate that the secondary nitrate and biogenic SOA,
biomass burning, and fungal spores were the main sources of OC in marine
aerosols over the East China Sea, again highlighting the importance of the Asian continent as a natural emitter of biogenic organic aerosols together with
anthropogenic aerosols over the coastal marine atmosphere.</p
Topological crystalline insulator states in Pb(1-x)Sn(x)Se
Topological insulators are a novel class of quantum materials in which
time-reversal symmetry, relativistic (spin-orbit) effects and an inverted band
structure result in electronic metallic states on the surfaces of bulk
crystals. These helical states exhibit a Dirac-like energy dispersion across
the bulk bandgap, and they are topologically protected. Recent theoretical
proposals have suggested the existence of topological crystalline insulators, a
novel class of topological insulators in which crystalline symmetry replaces
the role of time-reversal symmetry in topological protection [1,2]. In this
study, we show that the narrow-gap semiconductor Pb(1-x)Sn(x)Se is a
topological crystalline insulator for x=0.23. Temperature-dependent
magnetotransport measurements and angle-resolved photoelectron spectroscopy
demonstrate that the material undergoes a temperature-driven topological phase
transition from a trivial insulator to a topological crystalline insulator.
These experimental findings add a new class to the family of topological
insulators. We expect these results to be the beginning of both a considerable
body of additional research on topological crystalline insulators as well as
detailed studies of topological phase transitions.Comment: v2: published revised manuscript (6 pages, 3 figures) and
supplementary information (5 pages, 8 figures
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