181 research outputs found

    Computer simulations show that Neanderthal facial morphology represents adaptation to cold and high energy demands, but not heavy biting

    Get PDF
    Three adaptive hypotheses have been forwarded to explain the distinctive Neanderthal face: (i) an improved ability to accommodate high anterior bite forces, (ii) more effective conditioning of cold and/or dry air and, (iii) adaptation to facilitate greater ventilatory demands. We test these hypotheses using three-dimensional models of Neanderthals, modern humans, and a close outgroup (Homo heidelbergensis), applying finite-element analysis (FEA) and computational fluid dynamics (CFD). This is the most comprehensive application of either approach applied to date and the first to include both. FEA reveals few differences between H. heidelbergensis, modern humans, and Neanderthals in their capacities to sustain high anterior tooth loadings. CFD shows that the nasal cavities of Neanderthals and especially modern humans condition air more efficiently than does that of H. heidelbergensis, suggesting that both evolved to better withstand cold and/or dry climates than less derived Homo. We further find that Neanderthals could move considerably more air through the nasal pathway than could H. heidelbergensis or modern humans, consistent with the propositions that, relative to our outgroup Homo, Neanderthal facial morphology evolved to reflect improved capacities to better condition cold, dry air, and, to move greater air volumes in response to higher energetic requirements

    Quantum Convolutional Coding with Shared Entanglement: General Structure

    Full text link
    We present a general theory of entanglement-assisted quantum convolutional coding. The codes have a convolutional or memory structure, they assume that the sender and receiver share noiseless entanglement prior to quantum communication, and they are not restricted to possess the Calderbank-Shor-Steane structure as in previous work. We provide two significant advances for quantum convolutional coding theory. We first show how to "expand" a given set of quantum convolutional generators. This expansion step acts as a preprocessor for a polynomial symplectic Gram-Schmidt orthogonalization procedure that simplifies the commutation relations of the expanded generators to be the same as those of entangled Bell states (ebits) and ancilla qubits. The above two steps produce a set of generators with equivalent error-correcting properties to those of the original generators. We then demonstrate how to perform online encoding and decoding for a stream of information qubits, halves of ebits, and ancilla qubits. The upshot of our theory is that the quantum code designer can engineer quantum convolutional codes with desirable error-correcting properties without having to worry about the commutation relations of these generators.Comment: 23 pages, replaced with final published versio

    Role of genetic testing for inherited prostate cancer risk: Philadelphia prostate cancer consensus conference 2017

    Get PDF
    Purpose: Guidelines are limited for genetic testing for prostate cancer (PCA). The goal of this conference was to develop an expert consensus-dri

    First observation and amplitude analysis of the B−→D+K−π− decay

    Get PDF
    The B−→D+K−π− decay is observed in a data sample corresponding to 3.0  fb−1 of pp collision data recorded by the LHCb experiment during 2011 and 2012. Its branching fraction is measured to be B(B−→D+K−π−)=(7.31±0.19±0.22±0.39)×10−5 where the uncertainties are statistical, systematic and from the branching fraction of the normalization channel B−→D+π−π−, respectively. An amplitude analysis of the resonant structure of the B−→D+K−π− decay is used to measure the contributions from quasi-two-body B−→D∗0(2400)0K−, B−→D∗2(2460)0K−, and B−→D∗J(2760)0K− decays, as well as from nonresonant sources. The D∗J(2760)0 resonance is determined to have spin 1

    Diagnosis of obstructive coronary artery disease using computed tomography angiography in patients with stable chest pain depending on clinical probability and in clinically important subgroups: Meta-analysis of individual patient data

    Get PDF
    Objective To determine whether coronary computed tomography angiography (CTA) should be performed in patients with any clinical probability of coronary artery disease (CAD), and whether the diagnostic performance differs between subgroups of patients. Design Prospectively designed meta-analysis of individual patient data from prospective diagnostic accuracy studies. Data sources Medline, Embase, and Web of Science for published studies. Unpublished studies were identified via direct contact with participating investigators. Eligibility criteria for selecting studies Prospective diagnostic accuracy studies that compared coronary CTA with coronary angiography as the reference standard, using at least a 50% diameter reduction as a cutoff value for obstructive CAD. All patients needed to have a clinical indication for coronary angiography due to suspected CAD, and both tests had to be performed in all patients. Results had to be provided using 2×2 or 3×2 cross tabulations for the comparison of CTA with coronary angiography. Primary outcomes were the positive and negative predictive values of CTA as a function of clinical pretest probability of obstructive CAD, analysed by a generalised linear mixed model; calculations were performed including and excluding non-diagnostic CTA results. The no-treat/treat threshold model was used to determine the range of appropriate pretest probabilities for CTA. The threshold model was based on obtained post-test probabilities of less than 15% in case of negative CTA and above 50% in case of positive CTA. Sex, angina pectoris type, age, and number of computed tomography detector rows were used as clinical variables to analyse the diagnostic performance in relevant subgroups. Results Individual patient data from 5332 patients from 65 prospective diagnostic accuracy studies were retrieved. For a pretest probability range of 7-67%, the treat threshold of more than 50% and the no-treat threshold of less than 15% post-test probability were obtained using CTA. At a pretest probability of 7%, the positive predictive value of CTA was 50.9% (95% confidence interval 43.3% to 57.7%) and the negative predictive value of CTA was 97.8% (96.4% to 98.7%); corresponding values at a pretest probability of 67% were 82.7% (78.3% to 86.2%) and 85.0% (80.2% to 88.9%), respectively. The overall sensitivity of CTA was 95.2% (92.6% to 96.9%) and the specificity was 79.2% (74.9% to 82.9%). CTA using more than 64 detector rows was associated with a higher empirical sensitivity than CTA using up to 64 rows (93.4% v 86.5%, P=0.002) and specificity (84.4% v 72.6%, P<0.001). The area under the receiver-operating-characteristic curve for CTA was 0.897 (0.889 to 0.906), and the diagnostic performance of CTA was slightly lower in women than in with men (area under the curve 0.874 (0.858 to 0.890) v 0.907 (0.897 to 0.916), P<0.001). The diagnostic performance of CTA was slightly lower in patients older than 75 (0.864 (0.834 to 0.894), P=0.018 v all other age groups) and was not significantly influenced by angina pectoris type (typical angina 0.895 (0.873 to 0.917), atypical angina 0.898 (0.884 to 0.913), non-anginal chest pain 0.884 (0.870 to 0.899), other chest discomfort 0.915 (0.897 to 0.934)). Conclusions In a no-treat/treat threshold model, the diagnosis of obstructive CAD using coronary CTA in patients with stable chest pain was most accurate when the clinical pretest probability was between 7% and 67%. Performance of CTA was not influenced by the angina pectoris type and was slightly higher in men and lower in older patients. Systematic review registration PROSPERO CRD42012002780

    Measurement of the Difference of Time-Integrated CPAsymmetries in D0→K−K+ and D0→π−π+ Decays

    Get PDF
    A search for CP violation in D0KK+D^0 \rightarrow K^{-} K^{+} and D0ππ+D^0 \rightarrow \pi^{-} \pi^{+} decays is performed using pppp collision data, corresponding to an integrated luminosity of 3 fb13~fb^{-1}, collected using the LHCb detector at centre-of-mass energies of 7 and 8 8~TeV. The flavour of the charm meson is inferred from the charge of the pion in D+D0π+D^{*+}\rightarrow D^0\pi^+ and DD0ˉπD^{*-}\rightarrow \bar{D^0}\pi^{-} decays. The difference between the CP asymmetries in D0KK+D^0 \rightarrow K^{-} K^{+} and D0ππ+D^0 \rightarrow \pi^{-} \pi^{+} decays, ΔACPACP(KK+)ACP(ππ+)\Delta A_{CP} \equiv A_{CP}(K^{-} K^{+}) - A_{CP}(\pi^{-} \pi^{+}), is measured to be (0.10±0.08(stat)±0.03(syst))%\left( -0.10 \pm 0.08(stat) \pm 0.03(syst) \right) \%. This is the most precise measurement of a time-integrated CP asymmetry in the charm sector from a single experiment.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-055.htm

    Dalitz plot analysis ofB0→D¯0π+π−decays

    Get PDF
    The resonant substructures of B0D0π+πB^0 \to \overline{D}^0 \pi^+\pi^- decays are studied with the Dalitz plot technique. In this study a data sample corresponding to an integrated luminosity of 3.0 fb1^{-1} of pppp collisions collected by the LHCb detector is used. The branching fraction of the B0D0π+πB^0 \to \overline{D}^0 \pi^+\pi^- decay in the region m(D0π±)>2.1m(\overline{D}^0\pi^{\pm})>2.1 GeV/c2/c^2 is measured to be (8.46±0.14±0.29±0.40)×104(8.46 \pm 0.14 \pm 0.29 \pm 0.40) \times 10^{-4}, where the first uncertainty is statistical, the second is systematic and the last arises from the normalisation channel B0D(2010)π+B^0 \to D^*(2010)^-\pi^+. The π+π\pi^+\pi^- S-wave components are modelled with the Isobar and K-matrix formalisms. Results of the Dalitz plot analyses using both models are presented. A resonant structure at m(D0π)2.8m(\overline{D}^0\pi^-) \approx 2.8 GeV/c2/c^{2} is confirmed and its spin-parity is determined for the first time as JP=3J^P = 3^-. The branching fraction, mass and width of this structure are determined together with those of the D0(2400)D^*_0(2400)^- and D2(2460)D^*_2(2460)^- resonances. The branching fractions of other B0D0h0B^0 \to \overline{D}^0 h^0 decay components with h0π+πh^0 \to \pi^+\pi^- are also reported. Many of these branching fraction measurements are the most precise to date. The first observation of the decays B0D0f0(500)B^0 \to \overline{D}^0 f_0(500), B0D0f0(980)B^0 \to \overline{D}^0 f_0(980), B0D0ρ(1450)B^0 \to \overline{D}^0 \rho(1450), B0D3(2760)π+B^0 \to D_3^*(2760)^- \pi^+ and the first evidence of B0D0f0(2020)B^0 \to \overline{D}^0 f_0(2020) are presented.Comment: 64 pages, 17 figure
    corecore