3,375 research outputs found
Achievable efficiencies for probabilistically cloning the states
We present an example of quantum computational tasks whose performance is
enhanced if we distribute quantum information using quantum cloning.
Furthermore we give achievable efficiencies for probabilistic cloning the
quantum states used in implemented tasks for which cloning provides some
enhancement in performance.Comment: 9 pages, 8 figure
A hybrid recursive multilevel incomplete factorization preconditioner for solving general linear systems
In this paper we introduce an algebraic recursive multilevel incomplete factorization preconditioner, based on a distributed Schur complement formulation, for solving general linear systems. The novelty of the proposed method is to combine factorization techniques of both implicit and explicit type, recursive combinatorial algorithms, multilevel mechanisms and overlapping strategies to maximize sparsity in the inverse factors and consequently reduce the factorization costs. Numerical experiments demonstrate the good potential of the proposed solver to precondition effectively general linear systems, also against other state-of-the-art iterative solvers of both implicit and explicit form
Polymeric routes to silicon carbide and silicon oxycarbide CMC
An overview of two approaches to the formation of ceramic composite matrices from polymeric precursors is presented. Copolymerization of alkyl- and alkenylsilanes (RSiH3) represents a new precursor system for the production of Beta-SiC on pyrolysis, with copolymer composition controlling polymer structure, char yield, and ceramic stoichiometry and morphology. Polysilsesquioxanes which are synthesized readily and can be handled in air serve as precursors to Si-C-O ceramics. Copolymers of phenyl and methyl silsesquioxanes display rheological properties favorable for composite fabrication; these can be tailored by control of pH, water/methoxy ratio and copolymer composition. Composites obtained from these utilize a carbon coated, eight harness satin weave Nicalon cloth reinforcement. The material exhibits nonlinear stress-strain behavior in tension
The effects of weathering demonstrated by maternal age on low birth weight outcome in babies
BACKGROUND: Increasing age has been hypothesized with wear and tear (weathering) in mothers, which may result to low birthweight of their babies. The prevalence of low birthweight could be heightened if maternal weathering is associated with poor maternal socioeconomic variables. In this current study, we analyzed the effects of maternal weathering on babies’ birthweights.METHODS: One hundred and twenty four mother-baby pairs were selected using systematic random sampling method. Maternal age formed part of the demographic data that was obtained from the mothers’ case notes and from interviews held with them. Maternal socioeconomic variables were assessed using Oyedeji’s parameters and birthweights of babies were determined using bassinet weighing scale. Associations between maternal socioeconomic variables and birthweight of babies were assessed using univariate analysis. Differences in mean birthweight of babies according to their maternal age were evaluated using one-way analysis of variance ANOVA.RESULTS: Among the 124 babies, 66(53.2%) were males and 58(46.8%) females of whom the majority 104(83.9%, had normal birthweight. The mean birthweight of babies was 3.05±0.57 (95% CI, 2.95–3.15) kg, while the mean maternal age was 23.60 (5.2) 95% CI, (22.68–24.52) years. The difference between mean birthweight of babies and mean maternal age was not significant (F=1.35, p=0.255). Similarly, the association between birthweight, maternal education and occupation computed using univariate analysis was not significant (F=2.163, p=0.120) for education and (F=1.825, p=0.166) for occupation.CONCLUSION: In this study, maternal weathering was not found to be associated with LBW outcome. This implies that an increase in maternal age may not be significantly associated with LBW. However, there is need for further research on this subject from different centers using larger sample size in order to enhance the precision of the study.KEYWORDS: Mother-baby pairs, Maternal Weathering, Low birthweight, Maiduguri, Nigeri
Enhanced glutathione peroxidases (GPx) activity in young barley seedlings enriched with selenium
To assess whether young barley seedlings could be used as a selenium-enriched food material, a field experiment was carried out. Barley seeds were soaked in aqueous solutions at 20°C for 24 h. The solutions contained selenium in the form of sodium selenite and were at 0, 10, 20 and 30 μg/ml, respectively. Then the seeds were sowed in a non-selenium-fertilized field. Seedlings were harvested 2, 3, 4, and 5 weeks after sowing. Results show that selenium treatment did not affect (P>0.05) the biomass yield, height and stem diameter of young barley seedlings but significantly increased (P<0.05) selenium content and enhanced chlorophyll accumulation and glutathione peroxidases (GPx) activity in young barley seedlings. This study indicates that the method of soaking seeds in selenium solutions was feasible in enhancing selenium content in young barley seedlings which could be used as a seleniumenriched food material.Key words: Selenium, young barley seedlings, growth, chlorophyll, glutathione peroxidases
Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom
Negativity has been adopted to investigate the entanglement in a system
composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like
medium and the number of photon inside the cavity on the entanglement are
studied. Our results show that atomic initial state must be superposed, so that
the two cavity field modes can be entangled. Moreover, we also conclude that
the number of photon in the two cavity mode should be equal. The interaction
between modes, namely, the Kerr effect, has a significant negative
contribution. Note that the atom frequency and the cavity frequency have an
indistinguishable effect, so a corresponding approximation has been made in
this article. These results may be useful for quantum information in optics
systems.Comment: Accepted by Commun. Theor. Phy
Embracing corruption burstiness: Fast error recovery for ZigBee under wi-Fi interference
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.The ZigBee communication can be easily and severely interfered by Wi-Fi traffic. Error recovery, as an important means for
ZigBee to survive Wi-Fi interference, has been extensively studied in recent years. The existing works add upfront redundancy to
in-packet blocks for recovering a certain number of random corruptions. Therefore the bursty nature of ZigBee in-packet corruptions
under Wi-Fi interference is often considered harmful, since some blocks are full of errors which cannot be recovered and some blocks
have no errors but still requiring redundancy. As a result, they often use interleaving to reshape the bursty errors, before applying
complex FEC codes to recover the re-shaped random distributed errors. In this paper, we take a different view that burstiness may be
helpful. With burstiness, the in-packet corruptions are often consecutive and the requirement for error recovery is reduced as
”recovering any k consecutive errors” instead of ”recovering any random k errors”. This lowered requirement allows us to design far
more efficient code than the existing FEC codes. Motivated by this implication, we exploit the corruption burstiness to design a simple
yet effective error recovery code using XOR operations (called ZiXOR). ZiXOR uses XOR code and the delay is significantly reduced.
More, ZiXOR uses RSSI-hinted approach to detect in packet corruptions without CRC, incurring almost no extra transmission
overhead. The testbed evaluation results show that ZiXOR outperforms the state-of-the-art works in terms of the throughput (by 47%)
and latency (by 22%)This work was supported by the National Natural Science
Foundation of China (No. 61602095 and No. 61472360), the
Fundamental Research Funds for the Central Universities (No.
ZYGX2016KYQD098 and No. 2016FZA5010), National Key
Technology R&D Program (Grant No. 2014BAK15B02), CCFIntel
Young Faculty Researcher Program, CCF-Tencent Open
Research Fund, China Ministry of Education—China Mobile
Joint Project under Grant No. MCM20150401 and the EU FP7
CLIMBER project under Grant Agreement No. PIRSES-GA-
2012-318939. Wei Dong is the corresponding author
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