32,838 research outputs found

    Informed consent and the transmission of sexual disease: Dadson Revivified

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    This article examines the impact of the decisions in R v Dica (2004) and R v Konzani (2005) on the extent of the defence of consent. As well as analysing the impact of the decisions on the extent of the defence where a defendant faces criminal liability for the transmission of sexual disease, it also considers and examines the wider issue of whether the presence or absence of consent forms part of the actus reus of the relevant assault offence or whether it is a separate and independent element that stands outside of the conduct component of the offence. It is argued that recent developments have given insufficient consideration to accepted doctrine and revived much criticised principles by focusing on unknown circumstances of justification rather than the defendant's state of knowledge and mind

    Point interactions in acoustics: one dimensional models

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    A one dimensional system made up of a compressible fluid and several mechanical oscillators, coupled to the acoustic field in the fluid, is analyzed for different settings of the oscillators array. The dynamical models are formulated in terms of singular perturbations of the decoupled dynamics of the acoustic field and the mechanical oscillators. Detailed spectral properties of the generators of the dynamics are given for each model we consider. In the case of a periodic array of mechanical oscillators it is shown that the energy spectrum presents a band structure.Comment: revised version, 30 pages, 2 figure

    Path-Integral Formulation of Pseudo-Hermitian Quantum Mechanics and the Role of the Metric Operator

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    We provide a careful analysis of the generating functional in the path integral formulation of pseudo-Hermitian and in particular PT-symmetric quantum mechanics and show how the metric operator enters the expression for the generating functional.Comment: Published version, 4 page

    Correlation of transonic-cone preston-tube data and skin friction

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    Preston-tube measurements obtained on the Arnold Engineering Development Center (AEDC) Transition Cone have been correlated with theoretical skin friction coefficients in transitional and turbulent flow. This has been done for the NASA Ames 11-Ft Transonic Wind Tunnel (11 TWT) and flight tests. The developed semi-empirical correlations of Preston-tube data have been used to derive a calibration procedure for the 11 TWT flow quality. This procedure has been applied to the corrected laminar data, and an effective freestream unit Reynolds number is defined by requiring a matching of the average Preston-tube pressure in flight and in the tunnel. This study finds that the operating Reynolds number is below the effective value required for a match in laminar Preston-tube data. The distribution of this effective Reynolds number with Mach number correlates well with the freestream noise level in this tunnel. Analyses of transitional and turbulent data, however, did not result in effective Reynolds numbers that can be correlated with background noise. This is a result of the fact that vorticity fluctuations present in transitional and turbulent boundary layers dominate Preston-tube pressure fluctuations and, therefore, mask the tunnel noise eff ects. So, in order to calibrate the effects of noise on transonic wind tunnel tests only laminar data should be used, preferably at flow conditions similar to those in flight tests. To calibrate the effects of transonic wind-tunnel noise on drag measurements, however, the Preston-tube data must be supplemented with direct measurements of skin friction

    On separability of quantum states and the violation of Bell-type inequalities

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    In contrast to the wide-spread opinion that any separable quantum state satisfies every classical probabilistic constraint, we present a simple example where a separable quantum state does not satisfy the original Bell inequality although the latter inequality, in its perfect correlation form, is valid for all joint classical measurements. In a very general setting, we discuss inequalities for joint experiments upon a bipartite quantum system in a separable state. We derive quantum analogues of the original Bell inequality and specify the conditions sufficient for a separable state to satisfy the original Bell inequality. We introduce the extended CHSH inequality and prove that, for any separable quantum state, this inequality holds for a variety of linear combinations.Comment: 13 pages, extended versio

    Finite lifetime eigenfunctions of coupled systems of harmonic oscillators

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    We find a Hermite-type basis for which the eigenvalue problem associated to the operator HA,B:=B(x2)+Ax2H_{A,B}:=B(-\partial_x^2)+Ax^2 acting on L2(R;C2)L^2({\bf R};{\bf C}^2) becomes a three-terms recurrence. Here AA and BB are two constant positive definite matrices with no other restriction. Our main result provides an explicit characterization of the eigenvectors of HA,BH_{A,B} that lie in the span of the first four elements of this basis when ABBAAB\not= BA.Comment: 11 pages, 1 figure. Some typos where corrected in this new versio

    Strong-coupling asymptotic expansion for Schr\"odinger operators with a singular interaction supported by a curve in R3\mathbb{R}^3

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    We investigate a class of generalized Schr\"{o}dinger operators in L2(R3)L^2(\mathbb{R}^3) with a singular interaction supported by a smooth curve Γ\Gamma. We find a strong-coupling asymptotic expansion of the discrete spectrum in case when Γ\Gamma is a loop or an infinite bent curve which is asymptotically straight. It is given in terms of an auxiliary one-dimensional Schr\"{o}dinger operator with a potential determined by the curvature of Γ\Gamma. In the same way we obtain an asymptotics of spectral bands for a periodic curve. In particular, the spectrum is shown to have open gaps in this case if Γ\Gamma is not a straight line and the singular interaction is strong enough.Comment: LaTeX 2e, 30 pages; minor improvements, to appear in Rev. Math. Phy

    High-resolution 3D weld toe stress analysis and ACPD method for weld toe fatigue crack initiation

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    Weld toe fatigue crack initiation is highly dependent on the local weld toe stress-concentrating geometry including any inherent flaws. These flaws are responsible for premature fatigue crack initiation (FCI) and must be minimised to maximise the fatigue life of a welded joint. In this work, a data-rich methodology has been developed to capture the true weld toe geometry and resulting local weld toe stress-field and relate this to the FCI life of a steel arc-welded joint. To obtain FCI lives, interrupted fatigue test was performed on the welded joint monitored by a novel multi-probe array of alternating current potential drop (ACPD) probes across the weld toe. This setup enabled the FCI sites to be located and the FCI life to be determined and gave an indication of early fatigue crack propagation rates. To understand fully the local weld toe stress-field, high-resolution (5 mu m) 3D linear-elastic finite element (FE) models were generated from X-ray micro-computed tomography (mu-CT) of each weld toe after fatigue testing. From these models, approximately 202 stress concentration factors (SCFs) were computed for every 1 mm of weld toe. These two novel methodologies successfully link to provide an assessment of the weld quality and this is correlated with the fatigue performance

    A Composite Genome Approach to Identify Phylogenetically Informative Data from Next-Generation Sequencing

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    We have developed a novel method to rapidly obtain homologous genomic data for phylogenetics directly from next-generation sequencing reads without the use of a reference genome. This software, called SISRS, avoids the time consuming steps of de novo whole genome assembly, genome-genome alignment, and annotation. For simulations SISRS is able to identify large numbers of loci containing variable sites with phylogenetic signal. For genomic data from apes, SISRS identified thousands of variable sites, from which we produced an accurate phylogeny. Finally, we used SISRS to identify phylogenetic markers that we used to estimate the phylogeny of placental mammals. We recovered phylogenies from multiple datasets that were consistent with previous conflicting estimates of the relationships among mammals. SISRS is open source and freely available at https://github.com/rachelss/SISRS.Comment: 12 pages plus36 figures, 1 supplementary table, 3 supplementary figure
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