806 research outputs found

    Einstein-Podolsky-Rosen correlations of Dirac particles - quantum field theory approach

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    We calculate correlation function in the Einstein--Podolsky--Rosen type of experiment with massive relativistic Dirac particles in the framework of the quantum field theory formalism. We perform our calculations for states which are physically interesting and transforms covariantly under the full Lorentz group action, i.e. for pseudoscalar and vector state.Comment: 9 pages, 2 figures. Published versio

    Seasonal and dietary influences on adipose tissue and systemic gene expression in control and previously laminitic ponies

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    The aims of the study were to determine whether adipose tissue global gene expression (i) differs between never laminitic (NL) and previously laminitic (PL) ponies; (ii) is influenced by season and/or a diet designed to simulate spring grass and (iii) differences seen also occur systemically in peripheral blood mononuclear cells (PBMCs). Subcutaneous adipose tissue and PBMCs were obtained from six NL and six PL ponies on three occasions; summer, winter (season study) and in winter after consuming a diet simulating spring grass for seven days (diet study). Adipose tissue global gene expression was determined using a 44K equine specific microarray, validated using multiplex quantitative real time PCR (qRT-PCR) and analysed using GeneSpring software and Ingenuity Pathway Analysis. PBMC gene expression was quantified using qRT-PCR. The total number of genes whose expression differed (=2-fold change, p=0.01) between PL and NL ponies was greater in summer (192 genes) compared to winter (58 genes); 40/192 genes influenced by disease in the summer were also seasonally regulated and were predominantly associated with inflammation. The genes modified by dietary intervention and PBMC gene expression did not follow the same pattern as the season study. Thus, adipose tissue global gene expression differed between NL and PL ponies most in summer compared to winter, and these differentially expressed genes predominantly related to inflammation

    Type 2 Diabetes Risk Alleles Are Associated With Reduced Size at Birth

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    OBJECTIVE: Low birth weight is associated with an increased risk of type 2 diabetes. The mechanisms underlying this association are unknown and may represent intrauterine programming or two phenotypes of one genotype. The fetal insulin hypothesis proposes that common genetic variants that reduce insulin secretion or action may predispose to type 2 diabetes and also reduce birth weight, since insulin is a key fetal growth factor. We tested whether common genetic variants that predispose to type 2 diabetes also reduce birth weight. RESEARCH DESIGN AND METHODS: We genotyped single-nucleotide polymorphisms (SNPs) at five recently identified type 2 diabetes loci (CDKAL1, CDKN2A/B, HHEX-IDE, IGF2BP2, and SLC30A8) in 7,986 mothers and 19,200 offspring from four studies of white Europeans. We tested the association between maternal or fetal genotype at each locus and birth weight of the offspring. RESULTS: We found that type 2 diabetes risk alleles at the CDKAL1 and HHEX-IDE loci were associated with reduced birth weight when inherited by the fetus (21 g [95% CI 11-31], P = 2 x 10(-5), and 14 g [4-23], P = 0.004, lower birth weight per risk allele, respectively). The 4% of offspring carrying four risk alleles at these two loci were 80 g (95% CI 39-120) lighter at birth than the 8% carrying none (P(trend) = 5 x 10(-7)). There were no associations between birth weight and fetal genotypes at the three other loci or maternal genotypes at any locus. CONCLUSIONS: Our results are in keeping with the fetal insulin hypothesis and provide robust evidence that common disease-associated variants can alter size at birth directly through the fetal genotype

    Quantum key distribution system in standard telecommunications fiber using a short wavelength single-photon source

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    A demonstration of the principles of quantum key distribution is performed using a single-photon source in a proof of concept test-bed over a distance of 2 km in standard telecommunications optical fiber. The single-photon source was an optically-pumped quantum dot in a microcavity emitting at a wavelength of 895 nm. Characterization of the quantum key distribution parameters was performed at a range of different optical excitation powers. An investigation of the effect of varying the optical excitation power of the quantum dot microcavity on the quantum bit error rate and cryptographic key exchange rate of the system are presented.Comment: Final manuscript version, some grammatical differences from the published version. 26 pages including 7 figures

    Consistency of the Shannon entropy in quantum experiments

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    The consistency of the Shannon entropy, when applied to outcomes of quantum experiments, is analysed. It is shown that the Shannon entropy is fully consistent and its properties are never violated in quantum settings, but attention must be paid to logical and experimental contexts. This last remark is shown to apply regardless of the quantum or classical nature of the experiments.Comment: 12 pages, LaTeX2e/REVTeX4. V5: slightly different than the published versio
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