1,213 research outputs found

    On distinguishability, orthogonality, and violations of the second law: contradictory assumptions, contrasting pieces of knowledge

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    Two statements by von Neumann and a thought-experiment by Peres prompts a discussion on the notions of one-shot distinguishability, orthogonality, semi-permeable diaphragm, and their thermodynamic implications. In the first part of the paper, these concepts are defined and discussed, and it is explained that one-shot distinguishability and orthogonality are contradictory assumptions, from which one cannot rigorously draw any conclusion, concerning e.g. violations of the second law of thermodynamics. In the second part, we analyse what happens when these contradictory assumptions comes, instead, from _two_ different observers, having different pieces of knowledge about a given physical situation, and using incompatible density matrices to describe it.Comment: LaTeX2e/RevTeX4, 18 pages, 6 figures. V2: Important revisio

    Numerical Bayesian state assignment for a three-level quantum system. I. Absolute-frequency data; constant and Gaussian-like priors

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    This paper offers examples of concrete numerical applications of Bayesian quantum-state-assignment methods to a three-level quantum system. The statistical operator assigned on the evidence of various measurement data and kinds of prior knowledge is computed partly analytically, partly through numerical integration (in eight dimensions) on a computer. The measurement data consist in absolute frequencies of the outcomes of N identical von Neumann projective measurements performed on N identically prepared three-level systems. Various small values of N as well as the large-N limit are considered. Two kinds of prior knowledge are used: one represented by a plausibility distribution constant in respect of the convex structure of the set of statistical operators; the other represented by a Gaussian-like distribution centred on a pure statistical operator, and thus reflecting a situation in which one has useful prior knowledge about the likely preparation of the system. In a companion paper the case of measurement data consisting in average values, and an additional prior studied by Slater, are considered.Comment: 23 pages, 14 figures. V2: Added an important note concerning cylindrical algebraic decomposition and thanks to P B Slater, corrected some typos, added reference

    The Laplace-Jaynes approach to induction

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    An approach to induction is presented, based on the idea of analysing the context of a given problem into `circumstances'. This approach, fully Bayesian in form and meaning, provides a complement or in some cases an alternative to that based on de Finetti's representation theorem and on the notion of infinite exchangeability. In particular, it gives an alternative interpretation of those formulae that apparently involve `unknown probabilities' or `propensities'. Various advantages and applications of the presented approach are discussed, especially in comparison to that based on exchangeability. Generalisations are also discussed.Comment: 38 pages, 1 figure. V2: altered discussion on some points, corrected typos, added reference

    Numerical Bayesian quantum-state assignment for a three-level quantum system. II. Average-value data with a constant, a Gaussian-like, and a Slater prior

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    This paper offers examples of concrete numerical applications of Bayesian quantum-state assignment methods to a three-level quantum system. The statistical operator assigned on the evidence of various measurement data and kinds of prior knowledge is computed partly analytically, partly through numerical integration (in eight dimensions) on a computer. The measurement data consist in the average of outcome values of N identical von Neumann projective measurements performed on N identically prepared three-level systems. In particular the large-N limit will be considered. Three kinds of prior knowledge are used: one represented by a plausibility distribution constant in respect of the convex structure of the set of statistical operators; another one represented by a prior studied by Slater, which has been proposed as the natural measure on the set of statistical operators; the last prior is represented by a Gaussian-like distribution centred on a pure statistical operator, and thus reflecting a situation in which one has useful prior knowledge about the likely preparation of the system. The assigned statistical operators obtained with the first two kinds of priors are compared with the one obtained by Jaynes' maximum entropy method for the same measurement situation. In the companion paper the case of measurement data consisting in absolute frequencies is considered.Comment: 10 pages, 4 figures. V2: added "Post scriptum" under Conclusions, slightly changed Acknowledgements, and corrected some spelling error

    Cosmic variance of the galaxy cluster weak lensing signal

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    Intrinsic variations of the projected density profiles of clusters of galaxies at fixed mass are a source of uncertainty for cluster weak lensing. We present a semi-analytical model to account for this effect, based on a combination of variations in halo concentration, ellipticity and orientation, and the presence of correlated haloes. We calibrate the parameters of our model at the 10 per cent level to match the empirical cosmic variance of cluster profiles at M_200m=10^14...10^15 h^-1 M_sol, z=0.25...0.5 in a cosmological simulation. We show that weak lensing measurements of clusters significantly underestimate mass uncertainties if intrinsic profile variations are ignored, and that our model can be used to provide correct mass likelihoods. Effects on the achievable accuracy of weak lensing cluster mass measurements are particularly strong for the most massive clusters and deep observations (with ~20 per cent uncertainty from cosmic variance alone at M_200m=10^15 h^-1 M_sol and z=0.25), but significant also under typical ground-based conditions. We show that neglecting intrinsic profile variations leads to biases in the mass-observable relation constrained with weak lensing, both for intrinsic scatter and overall scale (the latter at the 15 per cent level). These biases are in excess of the statistical errors of upcoming surveys and can be avoided if the cosmic variance of cluster profiles is accounted for.Comment: 14 pages, 6 figures; submitted to MNRA

    A Creative Review on Integer Additive Set-Valued Graphs

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    For a non-empty ground set XX, finite or infinite, the {\em set-valuation} or {\em set-labeling} of a given graph GG is an injective function f:V(G)→P(X)f:V(G) \to \mathcal{P}(X), where P(X)\mathcal{P}(X) is the power set of the set XX. A set-indexer of a graph GG is an injective set-valued function f:V(G)→P(X)f:V(G) \to \mathcal{P}(X) such that the function f∗:E(G)→P(X)−{∅}f^{\ast}:E(G)\to \mathcal{P}(X)-\{\emptyset\} defined by f∗(uv)=f(u)∗f(v)f^{\ast}(uv) = f(u){\ast} f(v) for every uv∈E(G)uv{\in} E(G) is also injective, where ∗\ast is a binary operation on sets. An integer additive set-indexer is defined as an injective function f:V(G)→P(N0)f:V(G)\to \mathcal{P}({\mathbb{N}_0}) such that the induced function f+:E(G)→P(N0)f^+:E(G) \to \mathcal{P}(\mathbb{N}_0) defined by f+(uv)=f(u)+f(v)f^+ (uv) = f(u)+ f(v) is also injective, where N0\mathbb{N}_0 is the set of all non-negative integers. In this paper, we critically and creatively review the concepts and properties of integer additive set-valued graphs.Comment: 14 pages, submitted. arXiv admin note: text overlap with arXiv:1312.7672, arXiv:1312.767

    Detection of Methicillin-Resistant Staphylococcus aureus (MRSA) Using Loop Mediated Isothermal Amplification (LAMP)

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    Staphylococcus aureus is one of the most common pathogens that cause a wide range of infections ranging from skin and soft tissue infections to invasive, life threatening infections. The emergence of methicillin-resistant Staphylococcus aureus (MRSA) substantially increased healthcare burdens associated with Staphylococcal infections because of high morbidity and mortality and increasing the need for efficient and cost-effective screening methods, for high-risk patients. The objective of this study is to develop two molecular methods, real-time PCR and loop-mediated isothermal amplification (LAMP), and validate them following Clinical Laboratory Improvement Amendments (CLIA) and College of American Pathologists (CAP) standards. The real time PCR assay was developed targeting mecA, mecC, nuc, and coa to detect S. aureus and methicillin-resistance. The assay had high precision, a linear range of 104-108 CFU/ml, and 95% accuracy. The assay detects MRSA, MSSA, MR-CoNS, and MS CoNS. The LAMP assay was developed targeting the same genes; however, its lower limit of detection was 106 CFU/ml, which was much higher than that of the real-time PCR assay. Additional studies are required to optimize the performance characteristics of the LAMP assay further. Nevertheless, the real-time PCR assay developed in this study will be useful for the detection of MRSA in a cost-effective manner

    Strong Integer Additive Set-valued Graphs: A Creative Review

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    For a non-empty ground set XX, finite or infinite, the {\em set-valuation} or {\em set-labeling} of a given graph GG is an injective function f:V(G)→P(X)f:V(G) \to \mathcal{P}(X), where P(X)\mathcal{P}(X) is the power set of the set XX. A set-indexer of a graph GG is an injective set-valued function f:V(G)→P(X)f:V(G) \to \mathcal{P}(X) such that the function f∗:E(G)→P(X)−{∅}f^{\ast}:E(G)\to \mathcal{P}(X)-\{\emptyset\} defined by f∗(uv)=f(u)∗f(v)f^{\ast}(uv) = f(u){\ast} f(v) for every uv∈E(G)uv{\in} E(G) is also injective., where ∗\ast is a binary operation on sets. An integer additive set-indexer is defined as an injective function f:V(G)→P(N0)f:V(G)\to \mathcal{P}({\mathbb{N}_0}) such that the induced function gf:E(G)→P(N0)g_f:E(G) \to \mathcal{P}(\mathbb{N}_0) defined by gf(uv)=f(u)+f(v)g_f (uv) = f(u)+ f(v) is also injective, where N0\mathbb{N}_0 is the set of all non-negative integers and P(N0)\mathcal{P}(\mathbb{N}_0) is its power set. An IASI ff is said to be a strong IASI if ∣f+(uv)∣=∣f(u)∣ ∣f(v)∣|f^+(uv)|=|f(u)|\,|f(v)| for every pair of adjacent vertices u,vu,v in GG. In this paper, we critically and creatively review the concepts and properties of strong integer additive set-valued graphs.Comment: 13 pages, Published. arXiv admin note: text overlap with arXiv:1407.4677, arXiv:1405.4788, arXiv:1310.626
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