5,901 research outputs found
Nonorthogonal decoy-state Quantum Key Distribution
In practical quantum key distribution (QKD), weak coherent states as the
photon sources have a limit in secure key rate and transmission distance
because of the existence of multiphoton pulses and heavy loss in transmission
line. Decoy states method and nonorthogonal encoding protocol are two important
weapons to combat these effects. Here, we combine these two methods and propose
a efficient method that can substantially improve the performance of QKD. We
find a 79 km increase in transmission distance over the prior record using
decoy states method.Comment: 4 pages, 1 figure; Revtex4, submitted to PR
Surface Morphology of Laser-Superheated Pb(111) and Pb(100)
The surface step density on the vicinal Pb(111) and the surface vacancy density on Pb(100) after laser superheating and melting are investigated using reflection high-energy electron diffraction. With ∼100-ps laser pulses, Pb(111) surface superheating does not significantly change the density of the steps and step-edge roughness. However, after laser surface melting, the average terrace width and the string length at the step edge become as large as those at room temperature. The average terrace width at 573 K changes from 38±15 to 64±19 Å after laser surface melting, while the average string length at the step edge changes from 90±14 to 250±38 Å. For Pb(100), the surface vacancy density remains unchanged when the surface is superheated without melting. However, when the laser fluence is high enough to cause surface melting, the surface vacancy density increases. This increase in vacancy density is attributed to fast diffusion of atoms in the liquid film formed on Pb(100) during laser melting
The role of silicon as a nutrient/biostimulant in strawberries
• All plants grown in soil contain silicon (Si) in their tissues, with concentrations that vary from 0.1% to 10% of their dry weight. • Si is referred to as “quasi-essential” for the growth of higher plants due to its important role in alleviating abiotic and biotic stresses. It can be taken up in a bio-available form - H4SiO4 (Ma et al., 2011). • Work at the University of Hertfordshire showed that regular use of a Si nutrient enhanced constitutive (passive) defence pathway (i.e. morphological changes in the leaf structure) in strawberry plants, resulting in increased resilience to diseases (e.g. strawberry powdery mildew Podosphaera aphanis) and pests (e.g. twospotted spider mites Tetranychus urtiae). An increase in plant biomass and improvements on other agronomic traits were also found (results shown from 2018-2019 glasshouse hydroponic experiments). • Si is mainly laid down in epidermis and in the form of phytoliths.Peer reviewe
Characteristics of molecular changes in lespedeza plants after seeds been flown on satellite
No Abstrac
Asymmetry of Strange Sea in Nucleons
Based on the finite-temperature field theory, we evaluate the medium effects
in nucleon which can induce an asymmetry between quarks and antiquarks of the
strange sea. The short-distance effects determined by the weak interaction can
give rise to where is the medium-induced mass of strange quark by a few KeV at
most, but the long-distance effects by strong interaction are sizable. Our
numerical results show that there exists an obvious mass difference between
strange and anti-strange quarks, as large as 10-100 MeV.Comment: 15 latex pages, 3 figures, to appear in PR
Cardiac magnetic resonance analysis of left atrium function in patients with pre-apical hypertrophic cardiomyopathy
Background: Patients presenting with unexplained T wave inversion on electrocardiogram combined with thickened left ventricular apex but less than 15 mm had been proposed as a preclinical scope of apical hypertrophy cardiomyopathy (pre-ApHCM). However, analysis of left atrial (LA) function in these patients has not been studied. This study aims to evaluate the LA function in pre-ApHCM patients and compare it with patients with ApHCM using cardiac magnetic resonance (CMR) imaging.
Methods: In this retrospective case-control study, a total of 3,593 CMR reports from Beijing Anzhen Hospital, Capital Medical University, China were reviewed. Finally, 31 pre-ApHCM patients were identified and 40 ApHCM and 31 normal controls were included for comparison. LA volumetric and strain were analyzed by CMR. Two-tailed one-way ANOVA was used to analyze the difference of three groups. Pearson correlation test was used for correlation analysis.
Results: All of the volumetric parameters in pre-ApHCM group were higher than those in control group. LA reservoir (LA total EF, εs) and conduit function (LA passive EF, εe) parameters, were significantly different among the three groups, which were the lowest in the ApHCM group, intermediate in the pre-ApHCM group, and the highest in the control group ((all P<0.001). Compared with the control group, the LA booster pump function, both the booster EF and booster pump strain (εa) in ApHCM were impaired (P=0.003 and P=0.002 respectively). Meanwhile, only the εa was impaired (P=0.016) while LA booster EF was not (P=0.064) in the pre-ApHCM group, neither εa nor the booster EF show difference between the ApHCM and pre-ApHCM (P=0.272 and P=0.518 respectively).
Conclusions: LA function features in pre-ApHCM patients were similar to ApHCM but different from the normal controls. In pre-ApHCM and ApHCM patients, LA reservoir and conduit function impaired earlier before left atrium enlarged and decreased progressively as apex thickens. These findings may help to understand the LA functional change from pre-ApHCM to ApHCM, and to detect subclinical changes in patients with pre-ApHCM before overt hypertrophy or clinical symptoms develop
Culture-independent analysis of microflora in Gayals (Bos frontalis) feces
Comparative DNA sequence analysis of 16S/18S rRNA genes (rDNA) were undertaken to further our understanding of the make-up of micro-organisms communities in the feces of Gayals. Total DNA wereextracted from the feces of 5 Gayals. Two rDNA libraries (16S/18S rDNA) were constructed. In the 16S rDNA library, phylogenetic and sequence similarity analyses of the resultant 71 clone sequences revealed the presence of 67 operational taxonomic units (OTUs) or phylotypes and defined as having more than 97% of sequence similarity. The sequences were affiliated with the following phyla: Firmicutes (34.3%), Bacteroidetes (6.0%), Proteobacteria (4.5%), and uncultured bacteria (55.2%). A setof 58 sequences were analyzed in the 18S rDNA library, which were classified into 27 OTUs. They were mainly affiliated with the following phyla: Protozoa (25.9%), Basidiomycota (3.7%), Ascomycota (11.1%),and uncultured eukaryotes (59.3%). The sequence analysis indicated that more than half of the species, harbored in Gayals fecal belonged to the not-yet-cultured groups at 90% 16S/18S similarity levels with cultured species. In addition, micro-organisms of Chytridiomycetes was one of the most significant cellulose producing species obtained from the Gayal feces as well
Efficient electronic entanglement concentration assisted with single mobile electron
We present an efficient entanglement concentration protocol (ECP) for mobile
electrons with charge detection. This protocol is quite different from other
ECPs for one can obtain a maximally entangled pair from a pair of
less-entangled state and a single mobile electron with a certain probability.
With the help of charge detection, it can be repeated to reach a higher success
probability. It also does not need to know the coefficient of the original
less-entangled states. All these advantages may make this protocol useful in
current distributed quantum information processing.Comment: 6pages, 3figure
Ground-State Fidelity and Kosterlitz-Thouless Phase Transition for Spin 1/2 Heisenberg Chain with Next-to-the-Nearest-Neighbor Interaction
The Kosterlitz-Thouless transition for the spin 1/2 Heisenberg chain with the
next-to-the-nearest-neighbor interaction is investigated in the context of an
infinite matrix product state algorithm, which is a generalization of the
infinite time-evolving block decimation algorithm [G. Vidal, Phys. Rev. Lett.
\textbf{98}, 070201 (2007)] to accommodate both the
next-to-the-nearest-neighbor interaction and spontaneous dimerization. It is
found that, in the critical regime, the algorithm automatically leads to
infinite degenerate ground-state wave functions, due to the finiteness of the
truncation dimension. This results in \textit{pseudo} symmetry spontaneous
breakdown, as reflected in a bifurcation in the ground-state fidelity per
lattice site. In addition, this allows to introduce a pseudo-order parameter to
characterize the Kosterlitz-Thouless transition.Comment: 4 pages, 4 figure
A Single Scalar Field Model of Dark Energy with Equation of State Crossing -1
In this paper we study the possibility of building models of dark energy with
equation of state across -1 and propose explicitly a model with a single scalar
field which gives rise to an equation of state larger than -1 in the past and
less than -1 at the present time, consistent with the current observations.Comment: 4 pages, 1 figure, the version accepted by JCAP, presentation
improved and references adde
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