1,062 research outputs found
Hybrid quantum repeater with encoding
We present an encoded hybrid quantum repeater scheme using qubit-repetition
and Calderbank-Shor-Steane codes. For the case of repetition codes, we propose
an explicit implementation of the quantum error-correction protocol. Moreover,
we analyze the entangled-pair distribution rate for the hybrid quantum repeater
with encoding and we clearly identify a triple trade-off between the efficiency
of the codes, the memory decoherence time, and the local gate errors. Finally,
we show that in the presence of reasonable imperfections our system can achieve
rates of roughly 24 Hz per memory for 20 km repeater spacing, a final distance
of 1280 km, and a final fidelity of about 0.95.Comment: Published version. Eq.(10) revised, results unchange
Entanglement properties of optical coherent states under amplitude damping
Through concurrence, we characterize the entanglement properties of optical
coherent-state qubits subject to an amplitude damping channel. We investigate
the distillation capabilities of known error correcting codes and obtain upper
bounds on the entanglement depending on the non-orthogonality of the coherent
states and the channel damping parameter. This work provides a first, full
quantitative analysis of these photon-loss codes which are naturally
reminiscent of the standard qubit codes against Pauli errors.Comment: 7 pages, 6 figures. Revised version with small corrections; main
results remain unaltere
Alterations in fecal microbiota composition by probiotic supplementation in healthy adults:a systematic review of randomized controlled trials
BACKGROUND: The effects of probiotic supplementation on fecal microbiota composition in healthy adults have not been well established. We aimed to provide a systematic review of the potential evidence for an effect of probiotic supplementation on the composition of human fecal microbiota as assessed by high-throughput molecular approaches in randomized controlled trials (RCTs) of healthy adults. METHODS: The survey of peer-reviewed papers was performed on 17 August 2015 by a literature search through PubMed, SCOPUS, and ISI Web of Science. Additional papers were identified by checking references of relevant papers. Search terms included healthy adult, probiotic, bifidobacterium, lactobacillus, gut microbiota, fecal microbiota, intestinal microbiota, intervention, and (clinical) trial. RCTs of solely probiotic supplementation and placebo in healthy adults that examined alteration in composition of overall fecal microbiota structure assessed by shotgun metagenomic sequencing, 16S ribosomal RNA sequencing, or phylogenetic microarray methods were included. Independent collection and quality assessment of studies were performed by two authors using predefined criteria including methodological quality assessment of reports of the clinical trials based on revised tools from PRISMA/Cochrane and by the Jadad score. RESULTS: Seven RCTs investigating the effect of probiotic supplementation on fecal microbiota in healthy adults were identified and included in the present systematic review. The quality of the studies was assessed as medium to high. Still, no effects were observed on the fecal microbiota composition in terms of α-diversity, richness, or evenness in any of the included studies when compared to placebo. Only one study found that probiotic supplementation significantly modified the overall structure of the fecal bacterial community in terms of β-diversity when compared to placebo. CONCLUSIONS: This systematic review of the pertinent literature demonstrates a lack of evidence for an impact of probiotics on fecal microbiota composition in healthy adults. Future studies would benefit from pre-specifying the primary outcome and transparently reporting the results including effect sizes, confidence intervals, and P values as well as providing a clear distinction of between-group and within-group comparisons
Combining or Separating Forward and Reverse Logistics
Purpose
While forward logistics handles and manages the flow of goods downstream in the supply chain from suppliers to customers, reverse logistics (RL) manages the flow of returned goods upstream. A firm can combine RL with forward logistics, keep the flows separated, or choose a position between the two extremes. The purpose of this paper is to identify the contextual factors that determine the most advantageous position, which the paper refers to as the most advantageous degree of combination.
Design/methodology/approach
The paper first develops a scale ranging from 0 percent combination to 100 percent combination (i.e. full separation). Second, using the contingency theory the paper identifies the contextual factors described in RL-literature that determine the most advantageous degree of combination. The set of factors is subsequently tested using a case study, which applies a triangulation approach that combines a qualitative and a quantitative method.
Findings
The results show six distinct contextual factors that determine the most advantageous degree of combination. Examples of factors are technical product complexity, product portfolio variation, and the loss of product value over time.
Practical implications
For practitioners the scale of possible positions and set of contextual factors constitute a decision-making framework. Using the framework practitioners can determine the most advantageous position of the scale for their firm.
Originality/value
Much RL-research addresses intra-RL issues while the relationship between forward and RL is under-researched. This paper contributes to RL theory by identifying the contextual factors that determine the most advantageous relationship between forward and RL, and proposes a novel decision-making framework for practitioners.
</jats:sec
Osmotic stress tolerance in semi-terrestrial tardigrades
Heidemann, Nanna W. T., Smith, Daniel K., Hygum, Thomas L., Stapane, Lilian, Clausen, Lykke K. B., Jørgensen, Aslak, Helix-Nielsen, Claus, Møbjerg, Nadja (2016): Osmotic stress tolerance in semi-terrestrial tardigrades. Zoological Journal of the Linnean Society 178 (4): 912-918, DOI: 10.1111/zoj.12502, URL: http://dx.doi.org/10.1111/zoj.1250
Gut Microbiota in Human Adults with Type 2 Diabetes Differs from Non-Diabetic Adults
Recent evidence suggests that there is a link between metabolic diseases and bacterial populations in the gut. The aim of this study was to assess the differences between the composition of the intestinal microbiota in humans with type 2 diabetes and non-diabetic persons as control. was highly enriched in diabetic compared to non-diabetic persons (P = 0.02) and positively correlated with plasma glucose (P = 0.04).The results of this study indicate that type 2 diabetes in humans is associated with compositional changes in intestinal microbiota. The level of glucose tolerance should be considered when linking microbiota with metabolic diseases such as obesity and developing strategies to control metabolic diseases by modifying the gut microbiota
Pretransplant endotrophin predicts delayed graft function after kidney transplantation
Delayed graft function after kidney transplantation is common and increases morbidity and health care costs. There is evidence that endotrophin, a specific fragment of pro-collagen type VI, promotes the inflammatory response in kidney diseases. We tested the hypothesis that pretransplant endotrophin in kidney transplant recipients may be associated with the risk of delayed graft function. Pretransplant plasma endotrophin was assessed using an enzyme-linked immunosorbent assay in three independent cohorts with 806 kidney transplant recipients. The primary outcome was delayed graft function, i.e., the necessity of at least one dialysis session within one-week posttransplant. In the discovery cohort median pretransplant plasma endotrophin was higher in 32 recipients (12%) who showed delayed graft function when compared to 225 recipients without delayed graft function (58.4 ng/mL [IQR 33.4–69.0]; N = 32; vs. 39.5 ng/mL [IQR 30.6–54.5]; N = 225; P = 0.009). Multivariable logistic regression, fully adjusted for confounders showed, that pretransplant plasma endotrophin as a continuous variable was independently associated with delayed graft function in both validation cohorts, odds ratio 2.09 [95% CI 1.30–3.36] and 2.06 [95% CI 1.43–2.97]. Pretransplant plasma endotrophin, a potentially modifiable factor, was independently associated with increased risk of delayed graft function and may be a new avenue for therapeutic interventions
- …